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Deviation from Universality in Collisions of Ultracold $^6$Li$_2$ MoleculesJan 16 2013Apr 22 2013Collisions of $^6$Li$_2$ molecules with free $^6$Li atoms reveal a striking deviation from universal predictions based on long-range van der Waals interactions. Li$_2$ closed-channel molecules are formed in the highest vibrational state near a narrow ... More

Compressibility of an Ultracold Fermi Gas with Repulsive InteractionsApr 19 2012Fermi gases with repulsive interactions are characterized by measuring their compressibility as a function of interaction strength. The compressibility is obtained from in-trap density distributions monitored by phase contrast imaging. For interaction ... More

Magnetic field evolution of white dwarfs in strongly interacting binary star systemsNov 18 2009The surface magnetic field strength of white dwarfs is observed to vary from very little to around 10^9 G. Here we examine the proposal that the strongest fields are generated by dynamo action during the common envelope phase of strongly interacting stars ... More

Pauli paramagnetism of an ideal Fermi gasJan 07 2013We show how to use trapped ultracold atoms to measure the magnetic susceptibility of a two-component Fermi gas. The method is illustrated for a non-interacting gas of $^6$Li, using the tunability of interactions around a wide Feshbach resonances. The ... More

Formation of Ultracold Fermionic NaLi Feshbach MoleculesMay 23 2012May 25 2012We describe the formation of fermionic NaLi Feshbach molecules from an ultracold mixture of bosonic 23Na and fermionic 6Li. Precise magnetic field sweeps across a narrow Feshbach resonance at 745 G result in a molecule conversion fraction of 5% for our ... More

Photoassociation of Ultracold NaLiDec 19 2017Feb 13 2018We perform photoassociation spectroscopy in an ultracold $^{23}$Na-$^6$Li mixture to study the $c^3\Sigma^+$ excited triplet molecular potential. We observe 50 vibrational states and their substructure to an accuracy of 20 MHz, and provide line strength ... More

Towards a unified model of stellar rotation II: Model-dependent characteristics of stellar populationsApr 09 2012Rotation has a number of important effects on the evolution of stars. Apart from structural changes because of the centrifugal force, turbulent mixing and meridional circulation caused by rotation can dramatically affect a star's chemical evolution. This ... More

Towards a unified model of stellar rotationSep 05 2011The effects of rapid rotation on stellar evolution can be profound. We are now beginning to gather enough data to allow a realistic comparison between different physical models. Two key tests for any theory of stellar rotation are first whether it can ... More

The Most Magnetic StarsOct 10 2013Observations of magnetic A, B and O stars show that the poloidal magnetic flux per unit mass has an upper bound of 10^-6.5 G cm^2/g. A similar upper bound is found for magnetic white dwarfs even though the highest magnetic field strengths at their surfaces ... More

Magnetic Fields in Interacting BinariesJan 29 2018Wickramasinghe et al. (2014) and Briggs et al. (2015) have proposed that the strong magnetic fields observed in some single white dwarfs (MWDs) are formed by a dynamo driven by differential rotation when two stars, the more massive one with a degenerate ... More

Stellar evolution of massive stars with a radiative alpha-omega dynamoMay 29 2012Models of rotationally-driven dynamos in stellar radiative zones have suggested that magnetohydrodynamic transport of angular momentum and chemical composition can dominate over the otherwise purely hydrodynamic processes. A proper consideration of the ... More

Spindown of massive rotating starsMar 28 2011Models of rapidly rotating massive stars at low metallicities show significantly different evolution and higher metal yields compared to non-rotating stars. We estimate the spin-down time-scale of rapid rotating non-convective stars supporting an alpha-Omega ... More

The center of the wreath product of symmetric groups algebraNov 28 2018We consider the wreath product of two symmetric groups as a group of blocks permutations and we study its conjugacy classes. We give a polynomiality property for the structure coefficients of the center of the wreath product of symmetric groups algebra. ... More

A general framework for the polynomiality property of the structure coefficients of double-class algebrasApr 07 2015Take a sequence of couples $(G_n,K_n)_n$, where $G_n$ is a group and $K_n$ is a sub-group of $G_n.$ Under some conditions, we are able to give a formula that shows the form of the structure coefficients that appear in the product of double-classes of ... More

A Frobenius formula for the structure coefficients of double-class algebras of Gelfand pairsFeb 06 2015We generalise some well known properties of irreducible characters of finite groups to zonal spherical functions of Gelfand pairs. This leads to a Frobenius formula for Gelfand pairs. For a given Gelfand pair, the structure coefficients of its associated ... More

Structure coefficients of the Hecke algebra of $(S_{2n},B_n)$Dec 21 2012Mar 03 2014The Hecke algebra of the pair $(S_{2n},B_n)$, where $B_n$ is the hyperoctahedral subgroup of $S_{2n}$, was introduced by James in 1961. It is a natural analogue of the center of the symmetric group algebra. In this paper, we give a polynomiality property ... More

$k$-partial permutations and the center of the wreath product $\mathcal{S}_k\wr \mathcal{S}_n$ algebraFeb 06 2019We generalize the concept of partial permutations of Ivanov and Kerov and introduce $k$-partial permutations. This allows us to show that the structure coefficients of the center of the wreath product $\mathcal{S}_k\wr \mathcal{S}_n$ algebra are polynomials ... More

Polynomialité des coefficients de structure des algèbres de doubles-classesDec 05 2014In this thesis we studied the structure coefficients and especially their dependence on $n$ in the case of a sequence of double-class algebras. The first chapter is dedicated to the study of the structure coefficients in the general cases of centers of ... More

Merging Binary Stars and the magnetic white dwarfsDec 17 2014A magnetic dynamo driven by differential rotation generated when stars merge can explain strong fields in certain classes of magnetic stars, including the high field magnetic white dwarfs (HFMWDs). In their case the site of the differential rotation has ... More

Origin of magnetic fields in cataclysmic variablesSep 24 2018Oct 15 2018In a series of recent papers, it has been proposed that high field magnetic white dwarfs are the result of close binary interaction and merging. Population synthesis calculations have shown that the origin of isolated highly magnetic white dwarfs is consistent ... More

The Nature of Millisecond Pulsars with Helium White Dwarf CompanionsOct 31 2013We examine the growing data set of binary millisecond pulsars that are thought to have a helium white dwarf companion. These systems are believed to form when a low- to intermediate-mass companion to a neutron star fills its Roche lobe between central ... More

Formation of redbacks via accretion induced collapseOct 30 2014We examine the growing class of binary millisecond pulsars known as redbacks. In these systems the pulsar's companion has a mass between 0.1 and about 0.5 solar masses in an orbital period of less than 1.5 days. All show extended radio eclipses associated ... More

A two-dimensional mixing length theory of convective transportMar 01 2013The helioseismic observations of the internal rotation profile of the Sun raise questions about the two-dimensional (2D) nature of the transport of angular momentum in stars. Here we derive a convective prescription for axisymmetric (2D) stellar evolution ... More

Does GD 356 have a Terrestrial Planetary Companion?Feb 09 2010GD 356 is unique among magnetic white dwarfs because it shows Zeeman-split Balmer lines in pure emission. The lines originate from a region of nearly uniform field strength (delta B/B is approximately 0.1) that covers 10 per cent of the stellar surface ... More

Binary Star Origin of High Field Magnetic White DwarfsMay 01 2008White dwarfs with surface magnetic fields in excess of $1 $MG are found as isolated single stars and relatively more often in magnetic cataclysmic variables. Some 1,253 white dwarfs with a detached low-mass main-sequence companion are identified in the ... More

A Common Envelope Binary Star Origin of Long Gamma-ray BurstsSep 01 2010The stellar origin of gamma-ray bursts can be explained by the rapid release of energy in a highly collimated, extremely relativistic jet. This in turn appears to require a rapidly spinning highly magnetised stellar core that collapses into a magnetic ... More

The nature of the progenitor of the Type II-P supernova 1999emJul 26 2001Sep 25 2001We present high quality ground-based VRI images of the site of the Type II-P SN1999em (in NGC1637) taken before explosion, which were extracted from the CFHT archive. We determine a precise position of the SN on these images to an accuracy of 0.17''. ... More

Long-term Properties of Accretion Disks in X-ray Binaries: I. the variable third period in SMC X-1Oct 10 2002Long term X-ray monitoring data from the RXTE ASM and CGRO BATSE reveal that the third (superorbital) period in SMC X-1 is not constant, but varies between 40-60 days. A dynamic power spectrum analysis indicates that the third period has been present ... More

Generation and manipulation of Schrödinger cat states in Rydberg atom arraysMay 14 2019May 15 2019Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging, since such states are extremely fragile. Using a programmable quantum ... More

Generation and manipulation of Schrödinger cat states in Rydberg atom arraysMay 14 2019Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging, since such states are extremely fragile. Using a programmable quantum ... More

Implementation of New OPAL Tables in Eggleton's Stellar Evolution CodeOct 11 2006Nov 08 2006Based on the work of OPAL (Iglesias & Rogers 1996) and Alexander & Ferguson (1994), we construct a series of opacity tables for various metallicities Z=0, 0.00001, 0.00003, 0.0001, 0.0003, 0.001, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.1. ... More

The Theoretical Mass--Magnitude Relation of Low-Mass Stars and its Metallicity DependenceJan 28 1997We investigate the dependence of theoretically generated mass - (absolute magnitude) relations on stellar models. Using up to date physics we compute models in the mass range 0.1 < m < 1M_sun. We compare the solar-metallicity models with our older models, ... More

The Great Escape II: Exoplanet Ejection from Dying Multiple Star SystemsFeb 14 2012Extrasolar planets and belts of debris orbiting post-main-sequence single stars may become unbound as the evolving star loses mass. In multiple star systems, the presence or co-evolution of the additional stars can significantly complicate the prospects ... More

The Binary Second Sequence in Cluster Colour--Magnitude DiagramsJul 10 1998We show how the second sequence seen lying above the main sequence in cluster colour magnitude diagrams results from binaries with a large range of mass ratios and not just from those with equal masses. We conclude that the presence of a densely populated ... More

Reconstructing the evolution of white dwarf binaries: further evidence for an alternative algorithm for the outcome of the common-envelope phase in close binariesOct 12 2004We determine the possible masses and radii of the progenitors of white dwarfs in binaries from fits to detailed stellar evolution models and use these to reconstruct the mass-transfer phase in which the white dwarf was formed. We confirm the earlier finding ... More

Exploring the Divisions and Overlap between AGB and Super-AGB Stars and SupernovaeSep 24 2004We discuss the mass ranges over which we find AGB and super-AGB stars. The most massive super-AGB stars are candidate progenitors for type II core-collapse SNe. We discuss the two supernovae, SN1980K and SN2003gd that provide some restrictions on the ... More

On Rejuvenation in Massive Binary SystemsDec 19 2006We introduce a set of stellar models for massive stars whose evolution has been affected by mass transfer in a binary system, at a range of metallicities. As noted by other authors, the effect of such mass transfer is frequently more than just rejuvenation. ... More

Russell Lecture: Dark Star Formation and Cooling InstabilityMay 01 2001Optically thin cooling gas at most temperatures above 30K will make condensations by pressure pushing material into cool dense regions. This works without gravity. Cooling condensations will flatten and become planar/similarity solutions. Most star formation ... More

Hibernation Revived by Weak Magnetic BrakingSep 07 2006Cataclysmic variables undergo periodic nova explosions during which a finite mass of material is expelled on a short timescale. The system widens and, as a result, the mass-transfer rate drops. This state of hibernation may account for the variety of ... More

Modelling the progenitors of Core-Collapse SupernovaeSep 14 2004We present details of our investigation of the progenitors to core-collapse supernovae. We discuss observations and the theory of the lowest-mass stars to explode as supernovae.

Tidally enhanced stellar wind: a way to make the symbiotic channel to Type Ia supernova viableJun 07 2011In the symbiotic (or WD+RG) channel of the single degenerate scenario for type Ia supernovae (SNe Ia) the explosions occur a relatively long time after star formation. The birthrate from this channel would be too low to account for all observed SNe Ia ... More

The convective Urca processOct 31 2004One possible fate of an accreting white dwarf is explosion in a type Ia supernova. However, the route to the thermonuclear runaway has always been uncertain owing to the lack of a convective model consistent with the Urca process. We derive a formalism ... More

A two-stream formalism for the convective Urca processOct 31 2004We derive a new formalism for convective motions involving two radial flows. This formalism provides a framework for convective models that guarantees consistency for the chemistry and the energy budget in the flows, allows time-dependence and accounts ... More

Spin Angular Momentum Evolution of the Long Period AlgolsMar 23 2010We consider the spin angular momentum evolution of the accreting components of Algol-type binary stars. In wider Algols the accretion is through a disc so that the accreted material can transfer enough angular momentum to the gainer that material at its ... More

The Progenitors of Core-Collapse SupernovaeMay 20 2004May 22 2004We present maps of the nature of single star progenitors of supernovae and their remnants in mass and metallicity space. We find our results are similar to others but we have gone further in varying the amount of mixing and using various mass-loss schemes ... More

Core radii and common-envelope evolutionAug 31 2014Sep 16 2014Many classes of objects and events are thought to form in binary star systems after a phase in which a core and companion spiral to smaller separation inside a common envelope (CE).Such a phase can end with the merging of the two stars or with the ejection ... More

A more detailed look at the Opacities for Enriched Carbon and Oxygen MixturesOct 09 2003We have included opacity tables in our stellar evolution code that enable us to accurately model the structure of stars composed of mixtures with carbon and oxygen independently enhanced relative to solar. We present tests to demonstrate the effects of ... More

Angular Momentum Loss by Magnetic Braking and Gravitational Radiation in Relativistic Binary StarsNov 04 2008Angular momentum loss (AML) mechanisms and dynamical evolution owing to magnetic braking and gravitational radiation in relativistic binary stars (RBS) are studied with use of physical parameters collected from the literature. We have calculated and compared ... More

On the discovery of K-enhanced and possibly Mg-depleted stars throughout the Milky WayJul 16 2018Stars with unusual elemental abundances offer clues about rare astrophysical events or nucleosynthetic pathways. Stars with significantly depleted magnesium and enhanced potassium ([Mg/Fe] < -0.5; [K/Fe] > 1) have to date only been found in the massive ... More

Alignment Timescale of the Microquasar GRO J1655-40Feb 26 2008The microquasar GRO J1655-40 has a black hole with spin angular momentum apparently misaligned to the orbital plane of its companion star. We analytically model the system with a steady state disc warped by Lense-Thirring precession and find the timescale ... More

Formation rates of core collapse SNe and GRBsNov 19 2003We study the evolution of stars that may be the progenitors of long-soft gamma-ray burst (GRBs) -- rotating naked helium stars presumed to have lost their envelopes to winds or companions. Our aim is to investigate the formation and development of single ... More

Third Dredge-up in Low Mass Stars: Solving the LMC Carbon Star MysteryOct 08 2004A long standing problem with asymptotic giant branch (AGB) star models has been their inability to produce the low-luminosity carbon stars in the Large and Small Magellanic Clouds. Dredge-up must begin earlier and extend deeper. We find this for the first ... More

N-body Simulations with Live Stellar EvolutionFeb 05 2009An N-body code containing live stellar evolution through combination of the software packages NBODY6 and STARS is presented. Operational details of the two codes are outlined and the changes that have been made to combine them discussed. We have computed ... More

Convection physics and tidal synchronization of the subdwarf binary NY VirginisMar 14 2019Asteroseismological analysis of NY Vir suggests that at least the outer 55 per cent of the star (in radius) rotates as a solid body and is tidally synchronized to the orbit. Detailed calculation of tidal dissipation rates in NY Vir fails to account for ... More

Supernova Kicks and Misaligned MicroquasarsSep 30 2009The low-mass X-ray binary microquasar GRO J1655-40 is observed to have a misalignment between the jets and the binary orbital plane. Since the current black hole spin axis is likely to be parallel to the jets, this implies a misalignment between the spin ... More

The Shape of an Accretion Disc in a Misaligned Black Hole BinaryJul 29 2009We model the overall shape of an accretion disc in a semi-detached binary system in which mass is transfered on to a spinning black hole the spin axis of which is misaligned with the orbital rotation axis. We assume the disc is in a steady state. Its ... More

The effect of massive binaries on stellar populations and supernova progenitorsNov 20 2007We compare our latest single and binary stellar model results from the Cambridge STARS code to several sets of observations. We examine four stellar population ratios, the number of blue to red supergiants, the number of Wolf-Rayet stars to O supergiants, ... More

Evolution of binary stars and the effect of tides on binary populationsJan 14 2002We present a rapid binary evolution algorithm that enables modelling of even the most complex binary systems. In addition to all aspects of single star evolution, features such as mass transfer, mass accretion, common-envelope evolution, collisions, supernova ... More

Carbon Rich Extremely Metal Poor Stars: Signatures of Population-III AGB stars in Binary SystemsMar 27 2007We use the Cambridge stellar evolution code STARS to model the evolution and nucleosynthesis of zero-metallicity intermediate-mass stars. We investigate the effect of duplicity on the nucleosynthesis output of these systems and the potential abundances ... More

Post-common envelope binary systems experiencing helium-shell driven stable mass transferAug 17 2018We evolve stellar models to study the common envelope (CE) interaction of an early asymptotic giant branch star of initial mass $5\,\rm M_{\odot}$ with a companion star of mass ranging from $0.1$ to $2\,\rm M_{\odot}$. We model the CE as a fast stripping ... More

Quasi-stars, giants and the Schönberg-Chandrasekhar limitJan 26 2012Feb 13 2012The Sch\"onberg-Chandrasekhar (SC) limit is a well-established result in the understanding of stellar evolution. It provides an estimate of the point at which an evolved isothermal core embedded in an extended envelope begins to contract. We investigate ... More

Optical Spectroscopy of Embedded Young Stars in the Taurus-Auriga Molecular CloudApr 18 1998This paper describes the first optical spectroscopic survey of class I sources (also known as embedded sources and protostars) in the Taurus-Auriga dark cloud. We detect 10 of the 24 known class I sources in the cloud at 5500-9000 A. All detected class ... More

Stellar Evolution and Dynamics in Star ClustersOct 20 1997Dynamical models of star clusters are maturing in the sense that effects other than simple point particle dynamics are taken into account. We summarize the relevance of and prospects for this new generation of N-body models.

HR4049: signature of nova nucleosynthesis ?Aug 16 2004The post-Asymptotic Giant Branch (AGB) star HR4049 is in an eccentric binary system with a relatively short period probably surrounded by a dusty circumbinary disk. Extremely anomalous oxygen isotopic ratios, O16/O17 ~ O16/O18 ~ 7, have been measured ... More

Perturbations to Stellar Structure in 2D: Stellar Rotation and Heating in X-ray BinariesSep 16 2002We have developed a numerical code with which we study the effects of 2D perturbations on stellar structure. We present new numerical and analytical results on the heating of a main-sequence star in a binary system by its companion.

An Exoplanet's Response to Anisotropic Stellar Mass-Loss During Birth and DeathAug 02 2013The birth and death of planets may be affected by mass outflows from their parent stars during the T-Tauri or post-main-sequence phases of stellar evolution. These outflows are often modelled to be isotropic, but this assumption is not realistic for fast ... More

Critical Mass Transfer in Double-Degenerate Type Ia SupernovaeSep 07 2006Doubly-degenerate binary systems consisting of two white dwarfs both composed of carbon and oxygen and close enough that mass is transferred from the less massive to the more massive are possible progenitors of type Ia supernovae. If the mass transfer ... More

Slowing down atomic diffusion in subdwarf B stars: mass loss or turbulence?Aug 05 2011Subdwarf B stars show chemical peculiarities that cannot be explained by diffusion theory alone. Both mass loss and turbulence have been invoked to slow down atomic diffusion in order to match observed abundances. The fact that some sdB stars show pulsations ... More

Pre-mainsequence stellar evolution in N-body modelsFeb 13 2014We provide a set of analytic fits to the radii of pre-mainsequence stars in the mass range 0.1 < M/Msun < 8.0. We incorporate the formulae in N-body cluster models for evolution from the beginning of pre-main sequence. In models with 1,000 stars and high ... More

Supernova Kicks and Misaligned Be Star BinariesMay 14 2009Be stars are rapidly spinning B stars surrounded by an outflowing disc of gas in Keplerian rotation. Be star/X-ray binary systems contain a Be star and a neutron star. They are found to have non-zero eccentricities and there is evidence that some systems ... More

Accretion Disc Evolution in Single and Binary T Tauri StarsOct 30 1998We present theoretical models for the evolution of T Tauri stars surrounded by circumstellar discs. The models include the effects of pre-main-sequence stellar and time dependent disc evolution, and incorporate the effects of stellar magnetic fields acting ... More

Low and intermediate-mass close binary evolution and the initial - final mass relationOct 13 2000Using Eggleton's stellar evolution code, we carry out 150 runs of Pop I binary evolution calculations, with the initial primary mass between 1 and 8 solar masses the initial mass ratio between 1.1 and 4, and the onset of Roche lobe overflow (RLOF) at ... More

The Magnetic Fields of White Dwarfs in Cataclysmic VariablesOct 15 2018The origin of magnetic fields in isolated and binary white dwarfs has been investigated in a series of recent papers. One proposal is that magnetic fields are generated through an alpha-omega dynamo during common envelope evolution. Here we present population ... More

The Cosmic Microwave Background and the Stellar Initial Mass FunctionSep 10 2018Sep 24 2018We argue that an increased temperature in star-forming clouds alters the stellar initial mass function to be more bottom-light than in the Milky Way. At redshifts $z \gtrsim 6$, heating from the cosmic microwave background radiation produces this effect ... More

On the Blue Loops of Intermediate-Mass StarsFeb 15 2015We consider the blue loops in the Hertzsprung-Russell diagram that occur when intermediate-mass stars begin core helium burning. It has long been known that the excess of helium above the burning shell, the result of the contraction of the convective ... More

Alignment and Precession of a Black Hole with a Warped Accretion DiscAug 15 2007We consider the shape of an accretion disc whose outer regions are misaligned with the spin axis of a central black hole and calculate the steady state form of the warped disc in the case where the viscosity and surface densities are power laws in the ... More

The Ages of Pre-main-sequence StarsJul 30 1999The position of pre-main-sequence or protostars in the Hertzsprung--Russell diagram is often used to determine their mass and age by comparison with pre-main-sequence evolution tracks. On the assumption that the stellar models are accurate, we demonstrate ... More

Comprehensive analytic formulae for stellar evolution as a function of mass and metallicityJan 17 2000We present analytic formulae that approximate the evolution of stars for a wide range of mass and metallicity. Stellar luminosity, radius and core mass are given as a function of age, M and Z, for all phases from the zero-age main-sequence up to, and ... More

Deep Dredge-up in Intermediate-Mass TP-AGB StarsMay 07 2004We present results of the evolution of AGB stars of 3M_sol and 5M_sol with solar metallicity calculated with the Eggleton stellar evolution code (STARS), which has a fully implicit and simultaneous method for solving for the stellar structure, convective ... More

The evolution of low-metallicity asymptotic giant branch stars and the formation of carbon-enhanced metal-poor starsMar 13 2009We investigate the behaviour of asymptotic giant branch (AGB) stars between metallicities Z = 10-4 and Z = 10-8 . We determine which stars undergo an episode of flash-driven mixing, where protons are ingested into the intershell convection zone, as they ... More

An Explosive End to Intermediate-Mass Zero-Metallicity Stars and Early Universe NucleosynthesisDec 07 2007We use the Cambridge stellar evolution code STARS to model the evolution of 5-7 solar mass zero-metallicity stars. With enhanced resolution at the hydrogen and helium burning shell in the AGB phases, we are able to model the entire thermally pulsing asymptotic ... More

Runaway stars as progenitors of supernovae and gamma-ray burstsMar 09 2011When a core collapse supernova occurs in a binary system, the surviving star as well as the compact remnant emerging from the SN, may reach a substantial space velocity. With binary population synthesis modelling at solar and one fifth of solar metallicity, ... More

Tidal Interactions in Post Common-Envelope sdB BinariesAug 02 2018Over half of all observed hot subdwarf B (sdB) stars are found in binaries, and over half of these are found in close configurations with orbital periods of 10$ \,\rm{d}$ or less. In order to estimate the companion masses in these predominantly single-lined ... More

Enhanced Rotational Mixing in the Radiative Zones of Massive StarsJul 23 2018Oct 24 2018Convection in the cores of massive stars becomes anisotropic when they rotate. This anisotropy leads to a misalignment of the thermal gradient and the thermal flux, which in turn results in baroclinicity and circulation currents in the upper radiative ... More

Analogy Between Periodically Driven Josephson ac Effect and Quantum Hall EffectOct 15 1997Jan 16 1998The hydrodynamical phase-slippage geometry and a semi-classical Josephson-RCSJ formulism are combined to make an analogy between the periodically driven Josephson ac effect and the quantum Hall effect. Both of these two macroscopic quantum effects are ... More

Rotation of atoms in a two dimensional lattice with a harmonic trapOct 16 2006Mar 13 2007Rotation of atoms in a lattice is studied using a Hubbard model. It is found that the atoms are still contained in the trap even when the rotation frequency is larger than the trapping frequency. This is very different from the behavior in continuum. ... More

On the automorphism groups of some AG-codes based on $C_{a, b}$ curvesMay 16 2013Apr 17 2016We study $C_{a, b}$ curves and their applications to coding theory. Recently, Joyner and Ksir have suggested a decoding algorithm based on the automorphisms of the code. We show how $C_{a, b}$ curves can be used to construct MDS codes and focus on some ... More

Interacting fermionic topological insulators/superconductors in three dimensionsJan 06 2014May 29 2015Symmetry Protected Topological (SPT) phases are a minimal generalization of the concept of topological insulators to interacting systems. In this paper we describe the classification and properties of such phases for three dimensional(3D) electronic systems ... More

Time-reversal symmetric U(1) quantum spin liquidsMay 13 2015Mar 30 2016We study possible quantum $U(1)$ spin liquids in three dimensions with time-reversal symmetry. We find a total of 7 families of such $U(1)$ spin liquids, distinguished by the properties of their emergent electric/magnetic charges. We show how these spin ... More

Fractionalized gapless quantum vortex liquidsJul 28 2014May 12 2015The standard theoretical approach to gapless spin liquid phases of two-dimensional frustrated quantum antiferromagnets invokes the concept of fermionic slave particles into which the spin fractionalizes. As an alternate we explore new kinds of gapless ... More

The Affine BV-capacityOct 27 2015This paper is devoted to a geometric-measure-theoretic study of the brand new affine BV-capacity which is essentially different from the classic BV-capacity in dimension greater than one.

Half-filled Landau level, topological insulator surfaces, and three dimensional quantum spin liquidsJul 29 2015Oct 07 2015We synthesize and partly review recent developments relating the physics of the half-filled Landau level in two dimensions to correlated surface states of topological insulators in three dimensions. The latter are in turn related to the physics of certain ... More

Dual Dirac liquid on the surface of the electron topological insulatorMay 19 2015Oct 06 2015We discuss a non-fermi liquid gapless metallic surface state of the topological band insulator. It has an odd number of gapless Dirac fermions coupled to a non-compact U(1) gauge field. This can be viewed as a vortex dual to the conventional Dirac fermion ... More

Boson topological insulators: A window into highly entangled quantum phasesFeb 25 2013May 07 2013We study several aspects of the realization of global symmetries in highly entangled phases of quantum matter. Examples include gapped topological ordered phases, gapless quantum spin liquids and non-fermi liquid phases. An insightful window into such ... More

Comment on Yuan et alJan 10 2000The work of Yuan et al. (Phys. Rev. C 60 (1999) 045203) is being represented as definitive regarding the non-existence of a particular nonstrange, isoscalar, spin three dibaryon which has been proposed. We comment on this paper and its relation to our ... More

Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature SuperconductivityNov 15 2010Nov 17 2010Sr2IrO4 has been suggested as a Mott insulator from a single J_eff=1/2 band, similar to the cuprates. However this picture is complicated by the measured large magnetic anisotropy and ferromagnetism. Based on a careful mapping to the J_eff=1/2 (pseudospin-1/2) ... More

Composite fermi liquids in the lowest Landau levelApr 22 2016Jul 25 2016We study composite fermi liquid (CFL) states in the lowest Landau level (LLL) limit at a generic filling $\nu = \frac{1}{n}$. We begin with the old observation that, in compressible states, the composite fermion in the lowest Landau level should be viewed ... More

Antiferromagnetic magnons from fractionalized excitationsAug 31 2017Mar 23 2018We develop an approach to describe antiferromagnetic magnons on a bipartite lattice supporting the N\'{e}el state using fractionalized degrees of freedom typically inherent to quantum spin liquids. In particular we consider a long-range magnetically ordered ... More

Efficient quantum circuits for Szegedy quantum walksSep 01 2016A major advantage in using Szegedy's formalism over discrete-time and continuous-time quantum walks lies in its ability to define a unitary quantum walk on directed and weighted graphs. In this paper, we present a general scheme to construct efficient ... More

Broadband microwave absorption by logarithmic spiral metasurfaceSep 25 2018We propose to use a logarithmic spiral resonator for efficient absorption of microwave. By combining its scale-invariant geometry and Fabry-Perot-type resonances stemming from the fundamental TM mode, we realize a microwave metasurface with broadband ... More