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- Gordon Walter Semenoff

This faculty member is currently not actively recruiting graduate students or Postdoctoral Fellows, but might consider co-supervision together with another faculty member.

Professor

Moedal experiment, Large Hadron Collider, CERN

String theory, quantum field theory, statistical mechanics

Theoretical and mathematical physics, the physics of elementary particles, condensed matter physics

I am available and interested in collaborations (e.g. clusters, grants).

I am interested in and conduct interdisciplinary research.

I am interested in working with undergraduate students on research projects.

Physical reasoning and analytic problem solving using advanced methods of mathematical physics.

Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.

Aspects of quantum information in quantum field theory and quantum gravity (2019)

In this thesis we discuss applications of quantum information theoretic concepts toquantum gravity and the low-energy regime of quantum field theories.The first part of this thesis is concerned with how quantum information spreadsin four-dimensional scattering experiments for theories coupled to quantum electrodynamicsor perturbative quantum gravity. In these cases, every scattering processis accompanied by the emission of an infinite number of soft photons or gravitons,which cause infrared divergences in the calculation of scattering probabilities.There are two methods to deal with IR divergences: the inclusive and dressedformalisms. We demonstrate that in the late-time limit, independent of the method,the hard outgoing particles are entangled with soft particles in such a way that thereduced density matrix of the hard particles is essentially completely decohered.Furthermore, we show that the inclusive formalism is ill-suited to describe scatteringof wavepackets, requiring the use of the dressed formalism. We construct theHilbert space for QED in the dressed formalism as a representation of the canonicalcommutation relations of the photon creation/annihilation algebra, and argue that itsplits into superselection sectors which correspond to eigenspaces of the generatorsof large gauge transformations.In the second part of this thesis, we turn to applications of quantum informationtheoretic concepts in the AdS/CFT correspondence. In pure AdS, we find anexplicit formula for the Ryu-Takayanagi (RT) surface for special subregions in thedual conformal field theory, whose entangling surface lie on a light cone. Theexplicit form of the RT surface is used to give a holographic proof of Markovicityof the CFT vacuum on a light cone. Relative entropy of a state on such specialsubregions is dual to a novel measure of energy associated with a timelike vector flow between the causal and entanglement wedge. Positivity and monotonicity ofrelative entropy imply positivity and monotonicity of this energy, which yields aconsistency conditions for solutions to quantum gravity.

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Applications of path integral localization to gauge and string theories (2018)

In the first part of this thesis we exploit supersymmetric localization to study aspects of supersymmetric gauge theories relevant to holography. In chapter 2 we study the 1/2-BPS circular Wilson loop in the totally antisymmetric representation of the gauge group in N = 4 supersymmetric Yang-Mills. We compute the first 1/N correction at leading order in ’t Hooft coupling by means of the matrix model loop equations for comparison with the 1-loop effective action of the holographically dual D5-brane. Our result suggests the need to account for gravitational backreaction on the string theory side. In chapter 3 we solve the planar N = 2* super-Yang-Mills theory at large ’t Hooft coupling again using localization on S⁴. The solution permits detailed investigation of the resonance phenomena responsible for quantum phase transitions in infinite volume, and leads to quantitative predictions for the semiclassical string dual of the N = 2* theory. The second part of the thesis deals with the Schwinger effect in scalar quantum electrodynamics and in bosonic string theory. Chapter 4 presents a detailed study of the semiclassical expansion of the world line path integral for a charged relativistic particle in a constant external electric field. It is demonstrated that the Schwinger formula for charged particle pair production is reproduced exactly by the semiclassical expansion around classical instanton solutions when the leading order of fluctuations is taken into account. By a localization argument we prove that all corrections to this leading approximation vanish and that the WKB approximation to the world line path integral is exact. Finally, in chapter 5 we analyse the problem of charged string pair creation in a constant external electric field. We find the instantons in the worldsheet sigma model which are responsible for the tunneling events, and evaluate the sigma model partition function in the multi-instanton sector in the WKB approximation. We further identify a fermionic symmetry associated with collective coordinates, which we use to localize the worldsheet functional integral onto its WKB limit, proving that our result is exact.

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Infrared quantum information (2018)

Scattering amplitudes in massless gauge field theories have long been known to give rise to infrared divergent effects from the emission of very low energy gauge bosons. The traditional way of dealing with those divergences has been to abandon the idea of measuring amplitudes by only focusing on inclusive cross-sections constructed out of physically equivalent states. An alternative option, found to be consistent with the S-matrix framework, suggested to dress asymptotic states of charged particles by shockwaves of low energy bosons. In this formalism, the clouds of soft bosons, when tuned appropriately, cancel the usual infrared divergences occurring in the standard approach. Recently, the dressing approach has received renewed attention for its connection with newly discovered asymptotic symmetries of massless gauge theories and its potential role in the black hole information paradox.We start by investigating quantum information properties of scattering theory while having only access to a subset of the outgoing state. We give an exact formula for the von Neuman entanglement entropy of an apparatus particle scattered off a set of system particles and show how to obtain late-time expectation values of apparatus observables.We then specify to the case of quantum electrodynamics (QED) and gravity where the unobserved system particles are low energy photons and gravitons. Using the standard inclusive cross-section formalism, we demonstrate that those soft bosons decohere nearly all momentum superpositions of hard particles. Repeating a similar computation using the dressing formalism, we obtain an analogous result: In either framework, outgoing hard momentum states at late times are fully decohered from not having access to the soft bosons. Finally, we make the connection between our results and the framework of asymptotic symmetries of QED and gravity. We give new evidence for the use of the dressed formalism by exhibiting an inconsistency in the scattering of wavepackets in the original inclusive cross-section framework.

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2+1d Quantum Field Theories in Large N Limit (2017)

In Chapter 1, we present a brief introduction to the tight-binding model of graphene and show that in the low-energy continuum limit, it can be modeled by reduced QED₂₊₁ . We then review renormalization group technique which is used in the next chapters. In Chapter 2, we consider a quantum field theory in 3+1d with the defect of a large number of fermion flavors, N. We study the next-to-leading order contributions to the fermions current-current correlation function by performing a large N expansion. We find that the next-to-leading order contributions 1/N to the current-current correlation function is significantly suppressed. The suppression is a consequence of a surprising cancellation between the two contributing Feynman diagrams. We calculate the model's conductivity via the Kubo formula and compare our results with the observed conductivity for graphene. In Chapter 3, we study graphene's beta function in large N. We use the large N expansion to explore the renormalization of the Fermi velocity in the screening dominated regime of charge neutral graphene with a Coulomb interaction. We show that inclusion of the fluctuations of the magnetic field lead to a cancellation of the beta function to the leading order in 1/N. The first non-zero contribution to the beta function turns out to be of order 1/N². We perform a careful analysis of possible infrared divergences and show that the superficial infrared divergences do not contribute to the beta function. In Chapter 4, we study the phase structure of a Φ⁶ theory in large N. The leading order of the large N limit of the O(N) symmetric phi-six theory in three dimensions has a phase which exhibits spontaneous breaking of scale symmetry accompanied by a massless dilaton. In this chapter, we show that this “light dilaton” is actually a tachyon. This indicates an instability of the phase of the theory with spontaneously broken approximate scale invariance. We rule out the existence of Bardeen-Moshe-Bander phase. In this thesis, we show that Large N expansion is a powerful tool which in regimes that the system is interacting strongly could be used as an alternative to coupling expansion scheme.

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Holographic gauge/gravity duality and symmetry breaking in semimetals (2017)

We use the AdS/CFT correspondence (the holographic duality of gauge/gravity theory) to study exciton driven dynamical symmetry breaking in certain (2+1)-dimensional defect quantum field theories. These models can be argued to be analogs of the electrons with Coulomb interactions which occurin Dirac semimetals and the results our study of these model systems are indicative of behaviours that might be expected in semimetal systems such as monolayer and double monolayer graphene. The field theory models have simple holographic duals, the D3-probe-D5 brane system and the D3-probe-D7 brane system. Analysis of those systems yields information about the strong coupling planar limits of the defect quantum field theories. We study the possible occurrence of exciton condensates in the strong coupling limit of single-defect theories as well as double monolayer theories where we find a rich and interesting phase diagram. The phenomena which we study include the magnetic catalysis of chiral symmetry breaking in monolayers and inter-layer exciton condensation in double monolayers. In the latter case, we find a solvable model where the current-current correlations functions in the planar strongly coupled field theory can be computed explicitly and exhibit interesting behavior. Although the models that we analyze differ in detail from real condensed matter systems, we identify some phenomena which can occur at strong coupling in a generic system and which could well be relevant to the ongoing experiments on multi-monolayer Dirac semimetals. An example is the spontaneous nesting of Fermi surfaces in double monolayers. In particular, we suggest an easy to observe experimental signature of this phenomenon.

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Momentum-space entanglement and the gravity of entanglement in AdS/CFT (2014)

In the first part of this thesis we explore the entanglement structure of relativistic field theories in momentum space. We discuss a Wilsonian path integral formulation and a perturbative approach. Using perturbation theory we obtain results for specific quantum field theories. These are understood through scaling and decoupling properties of field theories. Convergence of the perturbation theory taking loop diagrams into account is also discussed. We then discuss the entanglement structure in systems where Lorentz invariance is broken by a Fermi surface. The Fermi surface helps the convergence of perturbation theory and entanglement of modes near the Fermi surface is shown to be amplified, even in the presence of a large momentum cutoff. In the second part of this thesis we explore the connection between entanglement and gravity in the context of the AdS/CFT correspondence. We show that there are certain thermodynamic-like relations common to all conformal field theories, which when mapped via the AdS/CFT correspondence to the bulk are tantamount to Einstein's equations, to lowest order in the metric.

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The AdS/CFT correspondence and string theory on the pp-wave (2008)

Aspects of the AdS/CFT correspondence are studied in the pp.-wave/BMN limit. We usethe light cone string field theory to investigate energy shifts of the one and two impuritystates. In the case of two impurity states we find that logarithmic divergences, in the sumsof intermediate states, actually cancel out between the Hamiltonian and a Q-dependentcontact term”. We show how non-perturbative terms, that have previously plagued thistheory, vanish as a consequence of this cancelation. We argue from this that every order ofinternal impurities contributes to the overall energy shift and attempt to give a systematicway of calculating such sums for the case of the simplest 3-string vertex (one proposed bydiVecchia).We extend our analysis of the mass shift to the case of the most advanced 3-stringvertex (proposed by Dobashi and Yoneya). We find agreement between our string fieldtheory calculations and the leading order CFT result in the BMN limit. We also find strongsimilarities between our result and higher orders in the field theory, including, on the stringside, the disappearance of the half-integer powers which generically do not exist in the fieldtheory calculations.We also study the orbifolding of the pp-wave background which results in the discretequantization of the light-cone momentum. We present the string field theory calculation forsuch a discreet momentum case. We also observe how a particular choice of the orbifold,results in the string theory corresponding to the quantization of the finite size giant magnonon the CFT side. We study this theory in detail with particular emphasis on its superalgebra.

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Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Towards a holographic universe (2022)

In this thesis, we present a bottom-up holographic model for a large class of time- reversal symmetric cosmological spacetimes, through the anti-de Sitter/conformal field theory (AdS/CFT) correspondence.A major challenge in describing cosmological spacetimes using the AdS/CFT correspondence, is that they often do not have an anti-de Sitter (AdS) boundary. To solve this problem we have constructed a geometry by embedding spherically symmetric regions of a Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime with a given scale factor inside a Schwarzschild-AdS (SAdS) spacetime, with the simple assumption that the two regions are separated by a thin shell satisfying Israel junction conditions. To ensure there exists a quantum state in the conformal field theory (CFT) which is dual to the bulk spacetime, we consider only time-reversal symmetric bubble spacetimes. This property allows us to define a real Euclidean spacetime by analytically continuing to imaginary times. We show that in certain cases, the Euclidean spacetime with its non-trivial asymptotic structure in form of the combined Euclidean AdS boundary of the FLRW cosmology and the SAdS boundary, gives rise to a natural state of the CFT via a Euclidean path integral. We also demonstrate the embedding procedure and existence of non-trivial asymptotics through some explicit examples.At this point two significant complications may arise. Firstly, to have the Euclidean asymptotics and time-reversal symmetry discussed above, we need cosmologies with a fundamentally negative cosmological constant, Λ. We argue that although the Λ-cold dark matter (ΛCDM) model points towards a small positive Λ, there is a plausible path forward with a model with a time dependent scalar field with a potential that is currently positive, but rolling towards a negative value to give us an effective negative Λ. Secondly, it is possible that our bubble lies behind the horizon of the SAdS black hole where we typically can’t probe. This problem is solved by a thorough analysis of the model’s parameter space, which suggests there is always a large set of parameters allowing embedding arbitrarily large bubbles of cosmology that peek out of the horizon.

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Full photon propagator and boundary charges in a 4D bulk with a 3D defect (2021)

We conduct a review of the basic concepts about boundary conformal field theory and boundary conformal anomalies. Next, we build a 4-D bulk and insert it with a 3-D fermion defect to consider the structure of full photon propagator and energy-momentum tensor in defect conformal field theory. Our result shows the interaction part of full photon propagator has a coeffi- cient which depends on the coefficient of one photon irreducible propagator. Comparing with the boundary CFT model, our defect CFT model loses part of the symmetry and the fold trick cannot be applied to the full photon prop- agator. In the end, we calculated the boundary central charges with the full photon propagator. We find all projective terms in full photon propagator under Feynman Gauge vanish when we calculate the two-point function of energy-momentum tensor. The result shows the boundary central charges also depend on the coefficient of one photon irreducible propagator. After ignoring the interaction fixing term, we find the boundary central charge reduces to half comparing to the boundary CFT model.

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Topics in boundary quantum field theory: magnetic edge states in graphene and BCFT orbifold (2021)

In this thesis, we investigate two examples of quantum field theory with planar boundaries. In the first part, we study the low energy excitations in a semi-infinite graphene sheet with the zigzag boundary condition. The system is described by a massless Dirac field with boundary condition such that half of the spinor components vanish on the boundary. From the residual continuous and discrete symmetries of the system, we argue that the graphene zigzag edge should be ferromagnetic. In the second part, we study symmetric orbifold boundary conformal field theory (BCFT). We show how to construct Cardy consistent boundary states for this symmetric orbifold BCFT. We also compute the boundary entropy and comment on its relevance to the AdS/BCFT correspondence.

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Infrared divergences in N=4 dupersymmetric Yang-Mills theory (2020)

A massive quark with U(1) charge is constructed with the Higgs mechanism in N = 4supersymmetric Yang-Mills theory and is set up in a constant, uniform external electricfield such that its classical trajectory is that of constant acceleration. The leading term inthe amplitude of the trajectory in the semi-classical approximation is quadratic in the totalproper time, which is attributed to infrared divergences. We consider various methods oftreating such divergences. The inclusion of Bremsstrahlung emission desirably replacesthe quadratic dependence with a linear one, but forces us to reconsider the meaning of aglobal color charge. The method of dressing by Wilson line is shown to be unsuccessful.We finally provide an Ansatz for a Chung-like dressing factor to lowest order and showthe elimination of infrared divergences.

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Exploring the dirac equation (2018)

In this thesis low energy excitations of perfectly dimerized trans-polyacetylene are modelled using the one-dimensional Dirac equation. The system is solved on both the half-line and segment, and the solutions are used to explore quantum phenomena. It is discovered that the zero mode of the half-line is a Majorana fermion quasiparticle. It is also found that dominate zero mode coupling to an electron on a scanning tunnelling microscope is achieved with a sufficiently large mass gap of the quantum wire. This allows scattering state excitations to be ignored in calculations in this thesis. It is also shown that the zero mode can facilitate entanglement of two electrons, each in proximity to opposite ends of a long segment of trans-polyacetylene. An algorithm is also developed which teleports the spin state of an electron on a segment of trans-polyacetylene. The quantum measurement used in this algorithm conserves fermion parity symmetry, however charge superselection is violated for three-fourths of the measurement operators. In the thermally isolated system teleportation is successful for all of the measurement operators on the ground state. However, decoherence occurs in the non-thermally isolated system due to thermal mixing of nearly degenerate states, leading to teleportation being successful for only half of the measurement operations on the thermal state.

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Lollipop diagrams in defect N=4 super Yang-Mills theory (2017)

In this thesis, we have studied the lollipop diagrams in defect $\mathcal{N}$=4 super Yang-Mills field theory with nontrivial background, which is dual to the D3-D5 brane system with the probe D5 brane carrying k units of flux. Using the framework for performing loop computations for this system built by Buhl-Mortensen, Leeuw, Ipsen, Kristjansen and Wilhelm, we prove that for arbitrary N and k, the contribution of the lollipop diagrams to the one-point function is zero. This improves their result, where they take the planar limit N>>1 and the probe brane limit k/N

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Momentum-Space Classification of Topologically Stable Fermi Surfaces (2015)

The purpose of the present work is to derive a classification for topologically stable Fermi surfaces for translationally invariant systems with no electron-electron interactions. To derive such a classification we introduce the necessary concepts in condensed matter and electronic band theory as well as those in mathematics such as topological spaces, building up to topological K-theory and its connections with Fredholm operators. We further compute such classes when there is only translational invariance for dimensions d = 1, 2, 3 and discuss the inclusion of other symmetries.

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Thermodynamic and Transport Properties of a Holographic Quantum Hall System (2015)

We apply the AdS/CFT correspondence to study a quantum Hall system at strong coupling. Fermions at finite density in an external magnetic field are put in via gauge fields living on a stack of D5 branes in Anti-deSitter space. Under the appropriate conditions, the D5 branes blow up to form a D7 brane which is capable of forming a charge-gapped state. We add finite temperature by including a black hole which allows us to compute the low temperature entropy of the quantum Hall system. Upon including an external electric field (again as a gauge field on the probe brane), the conductivity tensor is extracted from Ohm’s law.

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Non-Abelian D5 Brane Dynamics (2014)

The goal of this thesis is to analyse the non-abelian dual model to the defect probe D7-brane embedding in AdS₅ × S⁵[1]. The D7-brane picture can be thought of as a large number (N₅) of D5-branes growing a transverse fuzzy two-sphere, called BIon. This non-abelian solution improves our knowledge of the system by incorporating deviations in 1/N_{5}^{2} in the number of flavors. Such corrections are important from the point of view of the AdS/CFT correspondence as the CFT dual to the probe system is a candidate model for graphene, which possesses an emergent SU(4) symmetry. The main result of this work is the conductivity for the non-abelian D5 sytem. We fi nd that quantum Hall states have a non-integer transverse conductivity that depends on the number of flavor branes in the model. This deviationscales in 1/N_{5}^{2} in the number of flavor branes and vanishes in the large N₅ limit.

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Holographic descriptions of magnetic field on chiral field theory (2011)

In this thesis, we will study a top-down string theory holographic model of strongly interacting relativistic 2+1 dimensional fermions. We study the defect theory as examining a charged probe D7-branes/anti-branes modeland a charged probe D5-branes/anti-branes model on the thermal AdS₅×S⁵ geometry. We use the branes pair model to depict a geometrical chiral symmetry breaking. We are especially interested in the holographic magnetic effect on the flavour symmetries.

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Holographic fermions in d=2+1 (2011)

Recently, a large amount of effort has gone towards using the AdS/CFT conjecture in condensed matter physics. First, we present a review of the conjecture, then we use the conjecture to model 2+1-dimensional fermions. We find three kinds of solutions with different kinds of discrete symmetries. We show that Chern-Simons- like electric responses, computed using a holographic model appear with the right quantized coefficients.

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Large N Gauge Theory and k-Strings (2011)

We considered the k-antisymmetric representation of U(N) gauge group on two dimensional lattice space and derived the free energy by saddle point approximation in large N limit. k is a large integer comparable with N. Besides Gross-Witten phase transition[1], which happens as the coupling constant changes, we found a new phase transition in the strong coupling system that happens as k changes. The free energy of the weak coupling system is a smooth function of k under continuous limit. We have carefully selected the right saddle point solution among other possible ones. Thenumerical results match our saddle point calculations.

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Modular Invariance of Closed Bosonic String Theory with a PP-Wave Background (2010)

After a brief review of the necessary parts of the theory of the bosonic string, a consistent pp-wave background with constant dilaton and constant three-index antisymmetric field strength is introduced. In particular, the gravitational background is the plane wave with constant coefficients, and the antisymmetric field strength is chosen such that the worldsheet theory is both diff×Weyl invariant and stable. The one-loop closed bosonic string amplitude is evaluated and shown to be modular invariant. Then the free energy of a free closed string gas is calculated, modular invariance of it is proved, and the result is shown to be equivalent to the sum of free energies for the individual particle states.

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- Gravitational fields and quantum mechanics (2022)

International Journal of Modern Physics D, 31 (14) - Massless fermions on a half-space: the curious case of 2+1-dimensions (2022)

Journal of High Energy Physics, 2022 (10) - Search for highly-ionizing particles in pp collisions at the LHC’s Run-1 using the prototype MoEDAL detector (2022)

European Physical Journal C, 82 (8) - Search for magnetic monopoles produced via the Schwinger mechanism (2022)

Nature, 602 (7895), 63-67 - Soft scalars do not decouple (2022)

Physical Review D, 106 (10) - First Search for Dyons with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions (2021)

Physical Review Letters, 126 (7) - Timepix3 as a solid-state time-projection chamber in particle and nuclear physics (2021)

Proceedings of Science, 390 - Entanglement and the Infrared (2020)

Springer Proceedings in Mathematics and Statistics, 335, 151-166 - How to split the electron in half (2020)

Roman Jackiw: 80th Birthday Festschrift, 245-264 - On the infrared divergence and global colour in N = 4 Yang-Mills theory (2020)

Journal of High Energy Physics, 2020 (7) - Preface (2020)

Springer Proceedings in Physics, 239, vii-x - Defect QED: dielectric without a dielectric, monopole without a monopole (2019)

Journal of High Energy Physics, 2019 (11) - Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production (2019)

Physical Review Letters, 123 (2) - Dressed infrared quantum information (2018)

Physical Review D, 97 (2) - Dynamical Violation of Scale Invariance and the Dilaton in a Cold Fermi Gas (2018)

Physical Review Letters, 120 (20) - On the need for soft dressing (2018)

Journal of High Energy Physics, 2018 (9) - Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb−1 of 13 TeV proton–proton collisions at the LHC (2018)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 782, 510-516 - Worldsheet instantons and the amplitude for string pair production in an external field as a WKB exact functional integral (2018)

Journal of High Energy Physics, 2018 (5) - Infrared Quantum Information (2017)

Physical Review Letters, 119 (18) - Scattering and momentum space entanglement (2017)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 772, 699-702 - Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC (2017)

Physical Review Letters, 118 (6) - Light dilaton in the large N tricritical O (N) model (2016)

Physical Review D, 94 (12) - Phase structure of a holographic double monolayer Dirac semimetal (2016)

Journal of High Energy Physics, 2016 (6) - Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC (2016)

Journal of High Energy Physics, 2016 (8) - The D3-probe-D7 brane holographic fractional topological insulator (2016)

Journal of High Energy Physics, 2016 (10) - Topology of Fermi surfaces and anomaly inflows (2016)

Journal of High Energy Physics, 2016 (11) - Exciton condensation in a holographic double monolayer semimetal (2015)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 750, 22-25 - String worldsheet for accelerating quark (2015)

Journal of High Energy Physics, 2015 (10) - World-line instantons and the Schwinger effect as a Wentzel-Kramers-Brillouin exact path integral (2015)

Journal of Mathematical Physics, 56 (2) - A holographic quantum Hall ferromagnet (2014)

Journal of High Energy Physics, 2014 (2) - Conductivity tensor in a holographic quantum Hall ferromagnet (2014)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 738, 373-379 - Holographic D3-probe-D5 model of a double layer Dirac semimetal (2014)

Journal of High Energy Physics, 2014 (12) - The physics programme of the MoEDAL experiment at the LHC (2014)

International Journal of Modern Physics A, 29 (23) - Universal Bose gases near resonance: A rigorous solution (2014)

Physical Review A - Atomic, Molecular, and Optical Physics, 89 (3) - Chiral primary one-point functions in the D3-D7 defect conformal field theory (2013)

Journal of High Energy Physics, 2013 (1) - D3-D7 holographic dual of a perturbed 3D CFT (2013)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 88 (2) - D7-anti-D7 bilayer: Holographic dynamical symmetry breaking (2013)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 722 (4-5), 360-363 - Giant D5 brane holographic Hall state (2013)

Journal of High Energy Physics, 2013 (6) - Hot holographic giant loop (2013)

Journal of Physics: Conference Series, 462 (1) - Chiral symmetry breaking in graphene (2012)

Physica Scripta (T146) - D3-D5 holography with flux (2012)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 715 (1-3), 225-229 - Engineering holographic graphene (2012)

AIP Conference Proceedings, 1483, 305-329 - Spin versus charge-density-wave order in graphenelike systems (2012)

Physical Review B - Condensed Matter and Materials Physics, 86 (12) - Comments on k-strings at large N (2011)

Journal of High Energy Physics, 2011 (3) - Electronic zero modes of vortices in Hall states of gapped graphene (2011)

Physical Review B - Condensed Matter and Materials Physics, 83 (11) - Holographic fermionic fixed points in d=3 (2011)

Journal of High Energy Physics, 2011 (9) - Holographic Schwinger effect (2011)

Physical Review Letters, 107 (17) - Large representation recurrences in large N random unitary matrix models (2011)

Journal of High Energy Physics, 2011 (10) - Magnetic catalysis and quantum Hall ferromagnetism in weakly coupled graphene (2011)

Journal of High Energy Physics, 2011 (7) - On the spectrum of the AdS5 × S5 string at large λ (2011)

Journal of High Energy Physics, 2011 (3) - Hot giant loop holography (2010)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 82 (2) - Coulomb interaction at the metal-insulator critical point in graphene (2009)

Physical Review B - Condensed Matter and Materials Physics, 80 (8) - Finite size giant magnon (2009)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 79 (12) - Large representation Polyakov loop in hot Yang-Mills theory (2009)

Proceedings of Science - Domain walls in happed graphene (2008)

Physical Review Letters, 101 (8) - Electron fractionalization for two-dimensional Dirac fermions (2008)

Physical Review B - Condensed Matter and Materials Physics, 77 (23) - Finite size giant magnons in the string dual of N=6 superconformal Chern-Simons theory (2008)

Journal of High Energy Physics, 2008 (12) - Discrete symmetries and 1/3-quantum vortices in condensates of F=2 cold atoms (2007)

Physical Review Letters, 98 (10) - Gauge invariant finite size spectrum of the giant magnon (2007)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 651 (4), 329-335 - Stretched quantum states emerging from a Majorana medium (2007)

Journal of Physics B: Atomic, Molecular and Optical Physics, 40 (8), 1479-1488 - Testing AdS/CFT at string loops (2007)

Fortschritte der Physik, 55 (5-7), 742-747 - Uniaxial and biaxial spin nematic phases induced by quantum fluctuations (2007)

Physical Review Letters, 98 (16) - AdS/CFT v.s. string loops (2006)

Journal of High Energy Physics, 2006 (6) - Critical boundary sine-Gordon revisited (2006)

Annals of Physics, 321 (12), 2849-2875 - Cusped SYM Wilson loop at two loops and beyond (2006)

Nuclear Physics B, 748 (1-2), 170-199 - Exact 1 / 4 BPS loop-Chiral primary correlator (2006)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 643 (3-4), 195-204 - Finite size corrections and integrability of N = 2 SYM and DLCQ strings on a pp-wave (2006)

Journal of High Energy Physics, 2006 (9) - Quantum insulating states of F=2 cold atoms in optical lattices (2006)

Physical Review Letters, 97 (18) - Wilson loops in N = 4 SYM and fermion droplets (2006)

Journal of High Energy Physics, 2006 (6) - Divergence cancellation and loop corrections in string field theory on a plane wave background (2005)

Journal of High Energy Physics (12), 319-346 - Fermion representation of the rolling tachyon boundary conformal field theory (2005)

Journal of High Energy Physics (5), 2016-2052 - Free energy and phase transition of the matrix model on a plane wave (2005)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 71 (6), 1-11 - Wavy Wilson line and AdS/CFT (2005)

International Journal of Modern Physics A, 20 (13), 2833-2846 - DLCQ string spectrum from N = 2 SYM theory (2004)

Journal of High Energy Physics, 8 (11), 1369-1404 - BMN correlators and operator mixing in N = 4 super-Yang-Mills theory (2003)

Nuclear Physics B, 650 (1-2), 125-161 - On a modification of the boundary-state formalism in off-shell string theory (2003)

JETP Letters, 77 (1), 1-6 - String theory in electromagnetic fields (2003)

Journal of High Energy Physics, 7 (2), 529-575 - The boundary state formalism and conformal invariance in off-shell string theory (2003)

Journal of High Energy Physics, 7 (11), 459-475 - The superstring Hagedorn temperature in a pp-wave background (2003)

Journal of High Energy Physics, 7 (6), 147-169 - A new double-scaling limit of N = 4 super-Yang-Mills theory and pp-wave strings (2002)

Nuclear Physics B, 643 (1-3), 3-30 - DLCQ strings and branched covers of torii (2002)

Nuclear Physics B - Proceedings Supplements, 108, 99-105 - O(D) invariant tachyon condensates in the 1/D expansion (2002)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 543 (1-2), 127-134 - Wilson loops in SYM theory: From weak to strong coupling (2002)

Nuclear Physics B - Proceedings Supplements, 108, 106-112 - Color superconductivity and nondecoupling phenomena in (2+1)-dimensional QCD (2001)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 64 (2), 250051-2500510 - Color superconductivity and nondecoupling phenomena in (2+l)-dimensional QCD (2001)

Physical Review D, 64 (2) - Matrix strings in a b-field (2001)

Journal of High Energy Physics, 5 (7), 1-46 - More exact predictions of SUSYM for string theory (2001)

Nuclear Physics B, 616 (1-2), 34-46 - Non-commutative gross-neveu model at large n (2001)

Journal of High Energy Physics, 5 (6), 1-24 - Running couplings and triviality of field theories on noncommutative spaces (2001)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 64 (6), 5 - Running couplings and triviality of field theories on noncommutative spaces (2001)

Physical Review D, 64 (6) - The target space dependence of the Hagedorn temperature (2001)

Journal of High Energy Physics, 5 (11) - Extremal curves in (2 + 1)-dimensional Yang-Mills theory (2000)

Nuclear Physics B, 576 (1-3), 627-654 - Matrix theory interpretation of discrete light cone quantization string worldsheets (2000)

Physical Review Letters, 85 (16), 3343-3346 - Static potential in [formula presented] supersymmetric Yang-Mills theory (2000)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 61 (10) - Static potential in script N=4 supersymmetric Yang-Mills theory (2000)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 61 (10), 1-4 - Wilson loops in N=4 supersymmetric Yang-Mills theory (2000)

Nuclear Physics B, 582 (1-3), 155-175 - Loops, surfaces and grassmann representation in two- and three-dimensional ising models (1999)

International Journal of Modern Physics A, 14 (29), 4549-4574 - On the Correspondence between the Strongly Coupled 2-Flavor Lattice Schwinger Model and the Heisenberg Antiferromagnetic Chain (1999)

Annals of Physics, 275 (2), 254-296 - Screening and D-brane dynamics in finite temperature superstring theory (1999)

Physical Review D, 60 (10) - Screening and D-brane dynamics in finite temperature superstring theory (1999)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 60 (10) - Screening and D-brane dynamics in finite temperature superstring theory (1999)

Physical Review D, 60 (10) - Solitons on branes (1999)

Nuclear Physics B, 556 (1-2), 247-261 - Spectrum of the two-flavor Schwinger model from the Heisenberg spin chain (1999)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 59 (3) - Structure of the electric flux in script N sign = 4 supersymmetric Yang-Mills theory (1999)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 466 (2-4), 239-243 - Thermodynamic partition function of matrix superstrings (1999)

Nuclear Physics B, 561 (1-2), 243-272 - Thermodynamics of DO-branes in matrix theory (1999)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 445 (3-4), 307-315 - Two dimensional anti-de Sitter space and discrete light cone quantization (1999)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 468 (1-2), 52-57 - Universality and the magnetic catalysis of chiral symmetry breaking (1999)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 60 (10) - Universality in effective strings (1999)

JETP Letters, 69 (7), 509-515 - Phase transition induced by a magnetic field (1998)

Modern Physics Letters A, 13 (14), 1143-1154 - Topology and duality in abelian lattice theories 1 (1998)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 425 (3-4), 282-290 - D-brane configurations and Nicolai map in supersymmetric Yang-Mills theory (1997)

Modern Physics Letters A, 12 (3), 183-193 - Deconfinement transition for quarks on a line (1997)

Annals of Physics, 256 (1), 74-113 - Fermionic matrix models (1997)

International Journal of Modern Physics A, 12 (12), 2135-2291 - G/G models as the strong coupling limit of topologically massive gauge theory (1997)

Nuclear Physics B, 489 (1-2), 360-384 - Loop correlators and theta states in two-dimensional Yang-Mills theory (1997)

Annals of Physics, 260 (2), 275-310 - Quantum critical phenomena: The relationship between spin systems and strongly coupled gauge theories (1997)

Surveys in High Energy Physics, 10 (1-4), 265-278 - Vacuum structure and θ states of adjoint QCD in two dimensions (1997)

Nuclear Physics B, 487 (1-2), 191-206 - Vacuum structure of two-dimensional gauge theories for arbitrary Lie groups (1997)

Nuclear Physics B, 506 (1-2), 521-536 - Z-symmetry and polyakov loops in hot abelian gauge theories (1997)

International Journal of Modern Physics A, 12 (6), 1205-1214 - Adjoint non-Abelian Coulomb gas at large N (1996)

Nuclear Physics B, 480 (1-2), 317-337 - Charge screening and confinement in hot 3-D QED (1996)

Nuclear Physics B, 473 (1-2), 143-172 - Charge screening in the finite temperature Schwinger model (1996)

International Journal of Modern Physics A, 11 (22), 4103-4128 - Confinement-deconfinement transition in three-dimensional QED (1996)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 53 (12), 7157-7161 - Conformal motions and the Duistermaat-Heckman integration formula (1996)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 372 (3-4), 236-245 - Exact solution of the one-dimensional non-abelian coulomb gas at large N (1996)

Physical Review Letters, 77 (11), 2174-2177 - Gauged Yukawa matrix models and two-dimensional lattice theories (1996)

Physical Review D - Particles, Fields, Gravitation and Cosmology, 53 (10), 5886-5890 - Non-Abelian Coulomb gas (1996)

Physics Essays, 9 (4), 576-582 - Polymer statistics and fermionic vector models (1996)

Modern Physics Letters A, 11 (14), 1185-1197 - The braid group of a canonical Chern-Simons theory on a riemann surface (1996)

Annals of Physics, 245 (1), 1-22 - Unitary matrix integrals in the framework of the generalized Kontsevich model (1996)

International Journal of Modern Physics A, 11 (28), 5031-5080 - Canonical BF-type topological field theory and fractional statistics of strings (1995)

Nuclear Physics, Section B, 437 (3), 695-721 - Critical behaviour of a fermionic random matrix model at large-N (1995)

Physics Letters B, 351 (1-3), 153-161 - New universality classes for quantum critical behavior (1995)

Physical Review Letters, 74 (25), 4976-4979 - Observables and critical behaviour in fermionic matrix models (1995)

Theoretical and Mathematical Physics, 104 (1), 823-860 - Phase space isometries and equivariant localization of path integrals in two dimensions (1994)

Nuclear Physics, Section B, 421 (2), 391-412 - Phase transitions and mass generation in 2+1 dimensions (1994)

Physical Review D, 50 (2), 1060-1067 - QCD1+1 with massless quarks and gauge covariant Sugawara construction (1994)

Physics Letters B, 341 (2), 195-204 - Area law and continuum limit in "induced QCD" (1993)

Nuclear Physics, Section B, 395 (3), 547-580 - Canonical Chern-Simons theory and the braid group on a Riemann surface (1993)

Physics Letters B, 311 (1-4), 137-146 - Chiral dynamics and fermion mass generation in three-dimensional gauge theory (1993)

Physical Review Letters, 70 (25), 3848-3851 - Four-fermion theory and the conformal bootstrap (1993)

Annals of Physics, 228 (2), 341-364 - Gribov ambiguity and non-trivial vacuum structure of gauge theories on a cylinder (1993)

Physics Letters B, 303 (3-4), 303-307 - Induced QCD without local confinement (1993)

Physics Letters B, 302 (2-3), 283-290 - Radiative corrections to anyon scattering (1993)

Nuclear Physics, Section B, 392 (3), 700-724 - SU (N) antiferromagnets and the phase structure of QED in the strong coupling limit (1993)

Nuclear Physics, Section B, 406 (3), 595-630 - SU(N) Antiferromagnets and strongly coupled QED: Effective field theory for Josephson junctions arrays (1993)

Nuclear Physics B (Proceedings Supplements), 33 (3), 192-208 - Anyonization of lattice Chern-Simons theory (1992)

Annals of Physics, 217 (1), 66-104 - Charge distribution in two-dimensional electrostatics (1992)

Physical Review B, 45 (20), 12084-12087 - Dynamical violation of parity and chiral symmetry in three-dimensional four-Fermi theory (1992)

Physical Review D, 45 (4), 1342-1354 - Eta-invariants and fermion number in finite volume (1992)

Physics Letters B, 284 (3-4), 317-324 - Fractional spin, magnetic moment and the short-range interactions of anyons (1992)

Nuclear Physics, Section B, 368 (3), 718-742 - Gauge theories on a cylinder (1992)

Physics Letters B, 296 (1-2), 117-120 - Induced QCD and hidden local ZN symmetry (1992)

Physical Review Letters, 69 (24), 3435-3438 - Intersection forms and the geometry of lattice Chern-Simons theory (1992)

Physics Letters B, 286 (1-2), 118-124 - Investigations of pairing in anyon systems (1992)

Physical Review B, 46 (17), 11220-11223 - Strong coupling gauge theory, quantum spin systems and the spontaneous breaking of chiral symmetry (1992)

Physics Letters B, 297 (1-2), 175-180 - Two-loop analysis of non-Abelian Chern-Simons theory (1992)

Physical Review D, 46 (12), 5521-5539 - ZN domains in gauge theories with fermions at high temperatures (1992)

Physics Letters B, 277 (3), 331-336 - ZN phases in hot gauge theories (1992)

Physical Review D, 46 (4) - Anyonization and novel braid structure in dumb-bell Chern-Simons theory (1991)

Physics Letters B, 266 (3-4), 375-381 - Quantized magnetic susceptibility in (2+1)-dimensional gapless semiconductors (1991)

Physical Review Letters, 66 (20), 2653-2656 - Scale and conformal invariance in Chern-Simons-matter field theory (1991)

Physical Review D, 44 (6) - Topological quantum theories and integrable models (1991)

Physical Review D, 44 (12), 3899-3905 - White noise and heating of quantum field theory in an open system (1991)

Physical Review D, 44 (10), 3218-3229 - Dynamical mass generation in 3D four-fermion theory (1989)

Physical Review Letters, 63 (24), 2633-2636 - Exotic spin and statistics in (2+1)-dimensional canonical quantum field theory (1989)

Nuclear Physics, Section B, 328 (3), 753-776 - Fermionized spin systems and the boson-fermion mapping in (2+1)-dimensional gauge theory (1989)

Physics Letters B, 226 (1-2), 107-112 - Path integral analysis of chiral bosonization (1989)

Nuclear Physics, Section B, 312 (1), 197-226 - Renormalization of the statistics parameter in three-dimensional electrodynamics (1989)

Physical Review Letters, 62 (7), 715-718 - Semenoff replies (1989)

Physical Review Letters, 63 (9), 1026 - The Chern-Simons term versus the monopole (1989)

Nuclear Physics, Section B, 328 (3), 575-584 - Canonical quantum field theory with exotic statistics (1988)

Physical Review Letters, 61 (5), 517-520 - Chiral bosonization and local Lorentz-invariant actions for chiral bosons (1988)

Physical Review Letters, 60 (25), 2571-2574 - Comment on fractional statistics (1988)

Physical Review Letters, 60 (25), 2703 - Conformal field theory and the geometry of second quantization (1988)

Physical Review D, 37 (10), 2934-2945 - Erratum: Nonassociative electric fields in chiral gauge theory: An explicit construction (Physical Review Letters (1988) 60, 15 (1590)) (1988)

Physical Review Letters, 60 (15), 1590 - Index theorems and superconducting cosmic strings (1988)

Physical Review D, 37 (10), 2838-2852 - Lorentz invariant exact solution of the anomalous chiral Schwinger model (1988)

Zeitschrift für Physik C Particles and Fields, 39 (2), 269-273 - Nonassociative electric fields in chiral gauge theory: An explicit construction (1988)

Physical Review Letters, 60 (8), 680-683 - Induced fractional spin and statistics in three-dimensional QED (1987)

Physics Letters B, 184 (4), 397-402 - Quantum geometry of a conformal field theory (1987)

Physics Letters B, 198 (2), 209-214 - An exact solution of the chiral schwinger model (1986)

Physics Letters B, 175 (4), 439-444 - Cutkosky rules for condensed-matter systems (1986)

Physical Review B, 34 (6), 4338-4341 - Discontinuities of green functions in field theory at finite temperature and density (II) (1986)

Nuclear Physics, Section B, 272 (2), 329-364 - Fermion number fractionization in quantum field theory (1986)

Physics Reports, 135 (3), 99-193 - Gauge algebras in anomalous gauge-field theories (1986)

Physical Review Letters, 56 (10), 1019-1022 - Index theorems on open infinite manifolds (1986)

Nuclear Physics, Section B, 269 (1), 131-169 - Induced quantum curvature and three-dimensional gauge theories (1986)

Nuclear Physics, Section B, 276 (1), 173-196 - Non-Abelian adiabatic phases and the fractional quantum hall effect (1986)

Physical Review Letters, 57 (10), 1195-1198 - Squeezed strings (1986)

Physics Letters B, 176 (1-2), 108-114 - Thirring strings (1986)

Physics Letters B, 181 (3-4), 244-248 - Anomalies, Levinson's theorem, and fermion determinants (1985)

Physical Review D, 32 (2), 471-475 - Comment on "induced Chern-Simons terms at high temperatures and finite densities" (1985)

Physical Review Letters, 54 (19), 2166 - Discontinuities of green functions in field theory at finite temperature and density (1985)

Nuclear Physics, Section B, 260 (3-4), 714-746 - Erratum: Quantum holonomy and the chiral gauge anomaly (Physical Review Letters (1985) 55, 23, (2627)) (1985)

Physical Review Letters, 55 (23), 2627 - Evolution equation for the Higgs field in an expanding universe (1985)

Physical Review D, 31 (4), 699-703 - Feynman rules for finite-temperature Greens functions in an expanding universe (1985)

Physical Review D, 31 (4), 689-698 - Fractional fermion number in Kaluza-Klein theories (1985)

Physical Review D, 31 (6), 1324-1326 - Quantum holonomy and the chiral gauge anomaly (1985)

Physical Review Letters, 55 (9), 927-930 - Real-time Feynman rules for gauge theories with fermions at finite temperature and density (1985)

Zeitschrift für Physik C Particles and Fields, 29 (3), 371-380 - Spectral flow and the anomalous production of fermions in odd number of dimensions (1985)

Physical Review Letters, 54 (9), 873-876 - Condensed-Matter simulation of a three-Dimensional anomaly (1984)

Physical Review Letters, 53 (26), 2449-2452 - Electric Charge of the Magnetic Monopole (1984)

Physical Review Letters, 53 (6), 515-518 - Finite-temperature quantum field theory in Minkowski space (1984)

Annals of Physics, 152 (1), 105-129 - Fractional fermion number at finite temperature (1984)

Physics Letters B, 135 (1-3), 121-124 - Spectral asymmetry on an open space (1984)

Physical Review D, 30 (4), 809-818 - Thermodynamic calculations in relativistic finite-temperature quantum field theories (1984)

Nuclear Physics, Section B, 230 (2), 181-221 - Axial-anomaly-induced fermion fractionization and effective gauge-theory actions in odd-dimensional space-times (1983)

Physical Review Letters, 51 (23), 2077-2080 - Continuum quantum field theory for a linearly conjugated diatomic polymer with fermion fractionization (1983)

Physical Review Letters, 50 (6), 439-442 - Fluctuations of fractional charge in soliton anti-soliton systems (1983)

Nuclear Physics, Section B, 225 (2), 233-246 - Functional methods in thermofield dynamics: A real-time perturbation theory for quantum statistical mechanics (1983)

Nuclear Physics, Section B, 220 (2), 196-212 - Spectral asymmetry, trace identities and the fractional fermion number of magnetic monopoles (1983)

Physics Letters B, 132 (4-6), 369-373 - Fermion zero modes, supersymmetry, and charge fractionalization of quantum solitons (1982)

Physical Review D, 25 (4), 1054-1064 - Quantum numbers of solitons in a fermion-soliton system (1982)

Physical Review D, 26 (4), 938-940 - Secret supersymmetry and the fractional charges of quantum solitons (1982)

Physics Letters B, 113 (5), 371-374 - Asymptotic condition and Hamiltonian in quantum field theory with extended objects (1981)

Physical Review D, 24 (2), 406-415 - A perturbative look at the dynamics of extended systems in quantum field theory (1980)

Journal of Mathematical Physics, 22 (10), 2208-2222 - Quantum Electrodynamics in Solids (1980)

Fortschritte der Physik, 28 (2), 67-98 - Extended objects in quantum field theory (1979)

Journal of Mathematical Physics, 21 (7), 1761-1769 - A new double-scaling limit of N = 4 super-Yang-Mills theory and pp-wave strings

Nuclear Physics B, 661