Results for "Austen Lamacraft"

total 51took 0.07s
Learning Symmetries of Classical Integrable SystemsJun 11 2019The solution of problems in physics is often facilitated by a change of variables. In this work we present neural transformations to learn symmetries of Hamiltonian mechanical systems. Maintaining the Hamiltonian structure requires novel network architectures ... More
Boson pairing and unusual criticality in a generalized XY modelAug 29 2011Dec 16 2011We discuss the unusual critical behavior of a generalized XY model containing both 2\pi-periodic and \pi-periodic couplings between sites. The presence of vortices and half-vortices allows for single-particle condensate and pair-condensate phases. Using ... More
Nonequilibrium theory of Coulomb blockade in open quantum dotsFeb 22 2005Oct 05 2005We develop a non-equilibrium theory to describe weak Coulomb blockade effects in open quantum dots. Working within the bosonized description of electrons in the point contacts, we expose deficiencies in earlier applications of this method, and address ... More
Potential insights into non-equilibrium behavior from atomic physicsJun 17 2011This chapter seeks to outline a few basic problems in quantum statistical physics where recent experimental advances from the atomic physics community offer the hope of dramatic progress. The focus is on nonequilibrium situations where the powerful concepts ... More
The Fine Structure of the Phonon in One Dimension from Quantum HydrodynamicsMay 28 2014We show that the resonant interactions between phonons in one dimension may be treated consistently within Quantum Hydrodynamics by the introduction of phonon dispersion. In this way the physics of a nonlinear Luttinger liquid may be described in terms ... More
From GPE to KPZ: finite temperature dynamical structure factor of the 1D Bose gasJan 30 2012We study the finite temperature dynamical structure factor $S(k,\omega)$ of a 1D Bose gas using numerical simulations of the Gross--Pitaevskii equation appropriate to a weakly interacting system. The lineshape of the phonon peaks in $S(k,\omega)$ has ... More
Quantum Hydrodynamics in One Dimension beyond the Luttinger LiquidSep 28 2015Recent years have seen the development of a rich phenomenology beyond the Luttinger Liquid model of one dimensional quantum fluids, arising from interactions between the elementary phonon excitations. It has been known for some time, however, that the ... More
Order parameter statistics in the critical quantum Ising chainFeb 10 2008In quantum spin systems obeying hyperscaling, the probability distribution of the total magnetization takes on a universal scaling form at criticality. We obtain this scaling function exactly for the ground state and first excited state of the critical ... More
Unitary circuits of finite depth and infinite width from quantum channelsMar 27 2019We introduce an approach to compute reduced density matrices for local quantum unitary circuits of finite depth and infinite width. Suppose the time-evolved state under the circuit is a matrix-product state with bond dimension $D$; then the reduced density ... More
Nonlinear Luttinger Liquid from Painlevé IVJun 28 2016We show that exact time dependent single particle Green function in the Imambekov-Glazman theory of nonlinear Luttinger liquids can be written, for any value of the Luttinger parameter, in terms of a particular solution of the Painlev\'e IV equation. ... More
Weak Coulomb blockade effect in quantum dotsSep 09 2004Oct 05 2005We develop the general non-equilibrium theory of transport through a quantum dot, including Coulomb Blockade effects via a 1/N expansion, where N is the number of scattering channels. At lowest order we recover the Landauer formula for the current plus ... More
Universal phase structure of dilute Bose gases with Rashba spin-orbit couplingJun 13 2011Dec 21 2011A Bose gas subject to a light-induced Rashba spin-orbit coupling possesses a dispersion minimum on a circle in momentum space; we show that kinematic constraints due to this dispersion cause interactions to renormalize to universal, angle-dependent values ... More
Quantum Brownian motion in a quasiperiodic potentialJan 09 2019We consider a quantum particle subject to Ohmic dissipation, moving in a bichromatic quasiperiodic potential. In a periodic potential the particle undergoes a zero-temperature localization-delocalization transition as dissipation strength is decreased. ... More
Critical velocity of a mobile impurity in one-dimensional quantum liquidsOct 12 2011Mar 28 2012We study the notion of superfluid critical velocity in one spatial dimension. It is shown that for heavy impurities with mass $M$ exceeding a critical mass $M_\mathrm{c}$, the dispersion develops periodic metastable branches resulting in dramatic changes ... More
Radio frequency spectroscopy of a strongly imbalanced Feshbach-resonant Fermi gasMar 17 2008Aug 22 2008A sufficiently large species imbalance (polarization) in a two-component Feshbach resonant Fermi gas is known to drive the system into its normal state. We show that the resulting strongly-interacting state is a conventional Fermi liquid, that is, however, ... More
Spinodal decomposition in polarised Fermi superfluidsJan 28 2007May 29 2008We discuss the dynamics of phase separation through the process of spinodal decomposition in a Fermi superfluid with population imbalance. We discuss this instability first in terms of a phenomenological Landau theory. Working within the mean-field description ... More
Insights into glass formation and glass transition in supercooled liquids, by study of related phenomena in crystalsDec 27 2007We divide glass and viscous liquid sciences into two major research areas, the first dealing with how to avoid crystals and so access the viscous liquid state, and the second dealing with how liquids behave when no crystals form. We review some current ... More
Phases of quantum dimers from ensembles of classical stochastic trajectoriesFeb 26 2018Aug 17 2018We study the connection between the phase behaviour of quantum dimers and the dynamics of classical stochastic dimers. At the so-called Rokhsar-Kivelson (RK) point a quantum dimer Hamiltonian is equivalent to the Markov generator of the dynamics of classical ... More
Tail States in a Superconductor with Magnetic ImpuritiesJul 17 2000A field theoretic approach is developed to investigate the profile and spectrum of sub-gap states in a superconductor subject to a weak magnetic impurity potential. Such states are found to be associated with inhomogeneous supersymmetry broken instanton ... More
Superconductors with Magnetic Impurities: Instantons and Sub-gap StatesJan 07 2001When subject to a weak magnetic impurity potential, the order parameter and quasi-particle energy gap of a bulk singlet superconductor are suppressed. According to the conventional mean-field theory of Abrikosov and Gor'kov, the integrity of the energy ... More
Slow but complete, two state unfolding/refolding of lysozyme in "tuned" ~6M guanidinium carboxylate solutionsNov 23 2011Nov 25 2013We using differential scanning calorimetry of the unfolding process to identify conditions in which the pseudo two-state refolding of thermally denatured lysozyme can be observed to occur on time scales of hours, in solutions that approach 6M in guanidinium ... More
Potential tuning in the S-W system. (i) Bringing Tc,2 to ambient pressure, and (ii) colliding Tc,2 with the liquid-vapor spinodalMay 02 2016Jul 05 2016Following Vasisht et al's identification of the second critical point (Tc2,Pc2) for liquid silicon in the Stillinger-Weber (S-W) model for silicon, we study the variation of Tc2,Pc2 with tetrahedral repulsion parameter in an extension of the earlier "potential ... More
Glass Transitions and Critical Points in Orientationally Disordered Crystals and Structural Glassformers: "Strong" Liquids are More Interesting Than We ThoughtFeb 07 2013When liquids are classified using Tg -scaled Arrhenius plots of relaxation times (or relative rates of entropy increase above Tg) across a "strong-fragile" spectrum of behaviors, the "strong" liquids have always appeared rather uninteresting [1, 2]. Here ... More
On the decoupling of relaxation modes in a molecular liquid caused by isothermal introduction of 2nm structural inhomogeneitiesDec 13 2010To support a new interpretation of the origin of the dynamic heterogeneity observed pervasively in fragile liquids as they approach their glass transition temperatures Tg, we demonstrate that the introduction of ~2 nm structural inhomogeneities into a ... More
The phase diagram of 2D polar condensates in a magnetic fieldAug 31 2010Mar 14 2011Spin one condensates in the polar (antiferromagnetic) phase in two dimensions are shown to undergo a transition of the Ising type, in addition to the expected Kosterlitz--Thouless (KT) transition of half vortices, due to the quadratic Zeeman effect. We ... More
Non-Fermi liquid fixed point for an imbalanced gas of fermions in $1+ε$ dimensionsDec 17 2009Dec 26 2009We consider a gas of two species of fermions with population imbalance. Using the renormalization group in $d=1+\epsilon$ dimensions, we show that for spinless fermions and $\epsilon > 0$ a fixed point appears at finite attractive coupling where the quasiparticle ... More
When Agile Is Not Good Enough: an initial attempt at understanding how to make the right decisionFeb 22 2014Jul 02 2014Particularly over the last ten years, Agile has attracted not only the praises of a broad range of enthusiast software developers, but also the criticism of others. Either way, adoption or rejection of Agile seems sometimes to be based more on a questionable ... More
Tuning of tetrahedrality in a silicon potential yields a series of monatomic (metal-like) glassformers of very high fragilityOct 11 2005Aug 15 2006We obtain monatomic glass formers in simulations by modifying the tetrahedral character in a silicon potential to explore a triple point zone between potentials favoring diamond (dc) and bcc crystals. dc crystallization is always preceded by a polyamorphic ... More
Water and its relatives: the stable, supercooled and particularly the stretched, regimesApr 15 2014While the water molecule is simple, its condensed phase liquid behavior is so complex that no consensus description has emerged despite three centuries of effort. Here we identify features of its behavior that are the most peculiar, hence suggest ways ... More
Localization from sigma-model geodesicsFeb 24 2004Sep 09 2004We use a novel method based on the semi-classical analysis of sigma-models to describe the phenomenon of strong localization in quasi one-dimensional conductors, obtaining the full distribution of transmission eigenvalues. For several symmetry classes, ... More
Potential-tuning molecular dynamics studies of fusion, and the question of ideal glassformers: (I) The Gay-Berne modelNov 12 2010Jun 07 2011The ability of some liquids to vitrify during supercooling is usually seen as a consequence of the rates of crystal nucleation (and/or crystal growth) becoming small- thus a matter of kinetics. However there is evidence, dating back to the empirics of ... More
Directed destabilization of lysozyme in protic ionic liquids reveals a compact, low energy, soluble, reversibly-unfolding (pre-fibril) stateOct 20 2007Recent demonstrations of extraordinary stabilization of proteins in mobile protic [1] and aprotic [2] ionic liquid solutions at ambient temperatures have raised hopes of new biopreservation and drug transportation technologies. Here we examine the relation ... More
Many-body dynamics of p-wave Feshbach molecule production: a mean-field approachOct 08 2012Jan 16 2013We study the mean-field dynamics of p-wave Feshbach molecule production in an ultra cold gas of Fermi atoms in the same internal state. We derive a separable potential to describe the low-energy scattering properties of such atoms, and use this potential ... More
The Glass Transition Temperature of Water: A Simulation StudyMar 03 2004We report a computer simulation study of the glass transition for water. To mimic the difference between standard and hyperquenched glass, we generate glassy configurations with different cooling rates and calculate the $T$ dependence of the specific ... More
Thermodynamics and Dynamics of a Monoatomic Glass-Former. Constant Pressure and Constant Volume BehaviorNov 27 2007We report constant-volume and constant-pressure simulations of the thermodynamic and dynamic properties of the low-temperature liquid and crystalline phases of the modified Stillinger-Weber (mSW) model. We have found an approximately linear increase of ... More
Union of Random Trees and ApplicationsJan 22 2017Jun 05 2017In 1986, Janson showed that the number of edges in the union of $k$ random trees in the complete graph $K_n$ is a shifted version of a Poisson distribution. Using results from the theory of electrical networks, we provide a new proof of this result, obtaining ... More
Electrospray techniques for the study of liquid energetics by hyperquenched glass calorimetryNov 06 2002We describe an electrospray technique for in situ preparation, for differential scanning calorimetry study, of samples of molecular liquids quenched into the glassy state on extremely short time scales (hyperquenched). We study the case of propylene glycol ... More
Glass transitions, semiconductor-metal (SC-M) transitions and fragilities in Ge-V-Te (V=As, or Sb) liquid alloys: the difference one element can makeOct 26 2016Feb 10 2017Glass transition temperatures (Tg) and liquid fragilities are measured along a line of constant Ge content in the system Ge-As-Te, and contrasted with the lack of glass-forming ability in the twin system Ge-Sb-Te at the same Ge content. The one composition ... More
The Apparent Velocity and Acceleration of Relativistically Moving ObjectsFeb 22 2011Although special relativity limits the actual velocity of a particle to $c$, the velocity of light, the observed velocity need not be the same as the actual velocity as the observer is only aware of the position of a particle at the time in the past when ... More
Liquid-liquid transition in supercooled aqueous solution involving a low-temperature phase similar to low-density amorphous waterMay 29 2016The striking anomalies in physical properties of supercooled water that were discovered in the 1960-70s, remain incompletely understood and so provide both a source of controversy amongst theoreticians, and a stimulus to experimentalists and simulators ... More
Glass transitions, semiconductor-metal (SC-M) transitions and fragilities in Ge-V-Te (V=As, or Sb) liquid alloys: the difference one element can makeOct 26 2016Glass transition temperatures (Tg) and liquid fragilities are measured along a line of constant Ge content in the system Ge-As-Te, and contrasted with the lack of glass-forming ability in the twin system Ge-Sb-Te at the same Ge content. The one composition ... More
Glass transition with decreasing correlation length during cooling of Fe50Co50 superlattice and strong liquidsFeb 17 2010May 05 2010The glass transition GT is usually thought of as a structural arrest that occurs during the cooling of a liquid, or sometimes a plastic crystal, trapping a metastable state of the system before it can recrystallize to stabler forms1. This phenomenon occurs ... More
Finite temperature phase diagram of a polarised Fermi condensateMay 30 2006May 02 2007The two-component Fermi gas is the simplest fermion system displaying superfluidity, and as such finds applications ranging from the theory of superconductivity to QCD. Ultracold atomic gases provide an exceptionally clean realization of this system, ... More
Polarized Fermi condensates with unequal masses: Tuning the tricritical pointAug 30 2006May 02 2007We consider a two-component atomic Fermi gas within a mean-field, single-channel model, where both the mass and population of each component are unequal. We show that the tricritical point at zero temperature evolves smoothly from the BEC- to BCS-side ... More
Critical States in Disordered Superconducting FilmsJun 04 2004When subject to a pair-breaking perturbation, the pairing susceptibility of a disordered superconductor exhibits substantial long-ranged mesoscopic fluctuations. Focusing on a thin film subject to a parallel magnetic field, it is proposed that the quantum ... More
Entropy and dynamic properties of water below the homogeneous nucleation temperatureMar 31 1999Sep 10 1999Controversy exists regarding the possible existence of a transition between the liquid and glassy states of water. Here we use experimental measurements of the entropy, specific heat, and enthalpy of both liquid and glassy water to construct thermodynamically-plausible ... More
Physics of the Jagla Model as the Liquid-Liquid Coexistence Line Approaches HorizontalApr 27 2012The slope of the coexistence line of the liquid-liquid phase transition (LLPT) can be positive, negative, or zero. All three possibilities have been found in Monte-Carlo simulations of a modified spherically symmetric two-scale Jagla model. Since the ... More
Thermodynamics and Dynamics of the Two-Scale Spherically-Symmetric Jagla Model of Anomalous LiquidsMay 02 2006Using molecular dynamics simulations, we study a liquid model which consists of particles interacting via a spherically-symmetric two-scale Jagla ramp potential with both repulsive and attractive ramps. The Jagla potential displays anomalies similar to ... More
Search for a liquid-liquid critical point in models of silicaFeb 18 2014May 08 2014Previous research has indicated the possible existence of a liquid-liquid critical point (LLCP) in models of silica at high pressure. To clarify this interesting question we run extended molecular dynamics simulations of two different silica models (WAC ... More
Breakdown of the Stokes-Einstein Relation Above the Melting Temperature in a Liquid Phase-Change MaterialMay 03 2018The dynamic properties of liquid phase-change materials (PCMs), such as viscosity $\eta$ and atomic self-diffusion coefficients D, play an essential role in ultrafast phase switching behavior of novel non-volatile phase-change memory applications, as ... More
The Galaxy Cluster Concentration-Mass Scaling RelationOct 07 2015Nov 20 2015Scaling relations of clusters have made them particularly important cosmological probes of structure formation. In this work, we present a comprehensive study of the relation between two profile observables, concentration ($\mathrm{c_{vir}}$) and mass ... More