DOCSLIB.ORG

Tuning the Quantumness of Simple Bose Systems: a Universal Phase

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Tuning the Quantumness of Simple Bose Systems: a Universal Phase Tuning the quantumness of simple Bose systems: A universal phase diagram Youssef Koraa,1 , Massimo Boninsegnia , Dam Thanh Sonb,1 , and Shiwei Zhangc,d aDepartment of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada; bKadanoff Center for Theoretical Physics, The University of Chicago, Chicago, IL 60637; cCenter for Computational Quantum Physics, Flatiron Institute, New York, NY 10010; and dDepartment of Physics, The College of William and Mary, Williamsburg, VA 23187 Contributed by Dam Thanh Son, September 17, 2020 (sent for review August 20, 2020; reviewed by Joseph Carlson and Boris Svistunov) We present a comprehensive theoretical study of the phase dia- is the understanding of how quantum-mechanical effects alter gram of a system of many Bose particles interacting with a the qualitative behavior of the system predicted classically. For two-body central potential of the so-called Lennard-Jones form. systems obeying Fermi statistics, it is not yet possible to system- First-principles path-integral computations are carried out, pro- atically reach the accuracy necessary for reliable predictions of viding essentially exact numerical results on the thermodynamic new reactions, new structures, or new phases of matter; indeed, properties. The theoretical model used here provides a realistic this remains a grand challenge. However, if the constituent and remarkably general framework for describing simple Bose particles obey Bose statistics, it is now possible in principle systems ranging from crystals to normal fluids to superfluids and to obtain exact numerical estimates of thermodynamic aver- gases. The interplay between particle interactions on the one ages of relevant physical observables, for many relevant physical hand and quantum indistinguishability and delocalization on the systems. other hand is characterized by a single quantumness parameter, A broad class of condensed-matter systems is well character- which can be tuned to engineer and explore different regimes. ized by pairwise, central interactions among constituent particles Taking advantage of the rare combination of the versatility of (e.g., atoms), featuring 1) a strong repulsion at short interparti- the many-body Hamiltonian and the possibility for exact compu- cle separations (from Pauli exclusion principle, acting to prevent tations, we systematically investigate the phases of the systems electrons from different atomic or molecular clouds from over- as a function of pressure (P) and temperature (T), as well as the lapping spatially) and 2) a weak attractive tail at long distances, quantumness parameter. We show how the topology of the phase arising from mutually induced electric dipole moments. A widely PHYSICS diagram evolves from the known case of 4He, as the system is used approximate model to describe such an interaction is the made more (and less) quantum, and compare our predictions with Lennard-Jones (LJ) potential available results from mean-field theory. Possible realization and observation of the phases and physical regimes predicted here are σ 12 σ 6 VLJ (r) = 4 − , [1] discussed in various experimental systems, including hypothetical r r muonic matter. where is the depth of the attractive well, σ is the characteris- statistical physics j quantum many-body physics j quantum fluids and tic range of the interaction, and r is the separation between the solids j Bose–Einstein condensation j superfluidity two particles. Despite its simplicity, the LJ potential effectively accounts for the physical behavior of a large number of simple ne of the major themes of modern physics is the prediction liquids. Oof macroscopic properties and phases of thermodynamic A chief example of this type of condensed-matter system is assemblies of atoms and molecules directly from first princi- helium. Helium is unique among all substances, in that it does ples. A famous quote by Weisskopf from 1977 captures the not solidify at low temperature, under the pressure of its own aspiration and also underscores the challenge: “Assume that a group of intelligent theoretical physicists have lived in closed Significance buildings from birth that they never had occasion to see nat- ural structures:::What would they be able to predict from a Predicting the properties of a quantum-mechanical system fundamental knowledge of quantum mechanics? They would of many interacting particles is a major goal of modern sci- predict the existence of atoms, of molecules, of solid crys- ence and an outstanding challenge. We consider a compact tals, both metals and insulators, of gases, but most likely not and versatile model which captures the essential features of the existence of liquids.” (ref. 1, p. 202). Although Weisskopf a broad class of systems made of particles obeying Bose– focused on liquids, his remark highlighted the broader difficulty Einstein statistics and which allows one to systematically dial in treating interparticle interactions and emergent phenomena. up the effect of quantum entanglement in the presence of Interestingly, factoring in the possibility of computer simulations particle interaction by tuning a single parameter. We are able would almost certainly have changed this assessment. Simula- to obtain exact numerical results for the phase diagrams of tions using simple models of atomic interactions allow one to these systems. Possible directions for experimental realization make predictions of equilibrium structure and thermodynamic of the predictions are discussed. properties of many simple systems, including those of liquids. The rapid increase of modern computing power and devel- Author contributions: Y.K., M.B., D.T.S., and S.Z. designed research, performed research, opment of computational algorithms have greatly expanded the contributed new reagents/analytic tools, analyzed data, and wrote the paper.y role of computer simulations and computation, now encompass- Reviewers: J.C., Los Alamos National Laboratory; and B.S., University of Massachusetts ing many subareas of physics, chemistry, materials science, etc. Amherst. y Despite early fears, expressed, e.g., by Dirac that “the exact The authors declare no competing interest.y application of these laws leads to equations much too com- Published under the PNAS license.y plicated to be soluble,” (ref. 2, p. 714), we are now in the See online for related content such as Commentaries.y position to apply the fundamental laws of quantum mechanics to 1 To whom correspondence may be addressed. Email: [email protected] or dtson@ a large number of many-body systems, with precision sufficient uchicago.edu.y for fruitful comparison with experiment. Of particular interest First published October 21, 2020. www.pnas.org/cgi/doi/10.1073/pnas.2017646117 PNAS j November 3, 2020 j vol. 117 j no. 44 j 27231–27237 Downloaded by guest on October 2, 2021 vapor. Its most common isotope, 4He, undergoes a transition Z mµ me Meq = 1 + M , [3] to a superfluid phase at a temperature of 2.17 K. Both the fact A mN mµ that no crystallization occurs and the superfluid transition are 4 understood as consequences of Bose statistics (3, 4), which He where mµ and me are the masses of the muon and the electron, atoms (composite particles of zero total spin) obey. At higher respectively. The replacement of electrons by muons causes 1) temperature, 4He shows a behavior typical of other fluids; e.g., a shrinkage of the range (σ) of the interparticle potential by a it has a liquid–gas critical point at temperature about 5.19 K and factor of mµ=me (∼200) and 2) an increase in the well depth pressure 227 kPa. () by the same factor, resulting in a 200-fold increase of Λ— The question immediately arises of how general some of the sufficient to bring even systems made of heavier elements, e.g., properties of 4He are among Bose systems featuring the same Ne, whose condensed phase displays essentially classical physical kind of interaction, or how they might evolve with the mass of the behavior, into the highly quantum regime. particles and the interaction parameters, or whether new phases In this work, we perform a comprehensive study of the univer- might appear. sal phase diagram of LJ Bose systems. We use state-of-the-art A theoretical description of a system of interacting bosons quantum Monte Carlo (QMC) methods to compute numerically based on the LJ potential constitutes a simple but remarkably exact thermodynamic averages of relevant physical observables general framework in which such questions can be addressed. at finite temperatures. Given the presence of both strong inter- On taking (σ) as our unit of energy (length), the Hamiltonian actions and large quantum effects in these systems, systematically is fully parametrized by the dimensionless parameter∗ accurate many-body computations are crucial for reliable predic- tions. We map out the complete thermodynamic phase diagram 2 as a function of pressure and temperature, varying the parame- ~ ter Λ to explore a variety of physical regimes ranging from almost Λ = 2 , [2] mσ entirely classical to the ultraquantum. The remainder of this paper is organized as follows: in Theoret- whose magnitude expresses the relative importance of the kinetic ical Framework we describe the model of the system and briefly and potential energies. The larger the value of Λ is, the more summarize the methodology we utilized. In Results, we present significant the quantum effects in the dynamics of the particles and discuss our results in several subsections separated by the and the higher the temperature to which they can be expected different regimes of Λ, and we finally outline our conclusions in to persist. Conversely, in the Λ ! 0 limit the potential energy Discussion and Conclusions. dominates, and the behavior of the system is largely classical. To make this argument more quantitative, we note that for Theoretical Framework 4 He, ≡ He = 10:22 K and σ ≡ σHe = 2:556 A,˚ i.e., Λ = 0:18, Model. We consider an ensemble of N identical particles of mass which is the second highest value among naturally occurring sub- m obeying Bose statistics, enclosed in a cubic box of volume V , stances (the highest being 0.24 for the lighter helium isotope, with periodic boundary conditions in the three directions.
Load more

Recommended publications
  • Arxiv:0807.2458V2 [Cond-Mat.Dis-Nn] 29 Oct 2008 Se Oee,Tevr Eetwr Eotdi E.7)
    Theory of the superglass phase Giulio Biroli,1 Claudio Chamon,2 and Francesco Zamponi3 1Institut de Physique Th´eorique, CEA, IPhT, F-91191 Gif-sur-Yvette, France CNRS, URA 2306, F-91191 Gif-sur-Yvette, France 2Physics Department, Boston University, Boston, MA 02215, USA 3CNRS-UMR 8549, Laboratoire de Physique Th´eorique, Ecole´ Normale Sup´erieure, 24 Rue Lhomond, 75231 Paris Cedex 05, France (Dated: October 29, 2008) A superglass is a phase of matter which is characterized at the same time by superfluidity and a frozen amorphous structure. We introduce a model of interacting bosons in three dimensions that displays this phase unambiguously and that can be analyzed exactly or using controlled approxima- tions. Employing a mapping between quantum Hamiltonians and classical Fokker-Planck operators, we show that the ground state wavefunction of the quantum model is proportional to the Boltzmann measure of classical hard spheres. This connection allows us to obtain quantitative results on static and dynamic quantum correlation functions. In particular, by translating known results on the glassy dynamics of Brownian hard spheres we work out the properties of the superglass phase and of the quantum phase transition between the superfluid and the superglass phase. I. INTRODUCTION Solids do not flow. This apparently tautological statement can be wrong in two ways. First, solidity is in general a timescale-dependent phenomenon. Crystal or glasses, well known solids on most experimentally relevant timescales, do flow if one waits long enough (see Ref. 1 for example). Second, at very small temperatures, quantum solids may become superfluids as suggested theoretically in the early seventies2–4.
    [Show full text]
  • Insulation Solutions Guide
    Creating Intelligent Environments Insulation Solutions Guide Has anyone ever put more thought into insulation? Our world has changed. The way we live is affecting our planet more than ever, and the buildings we construct need to address this – now. 2 Technical Department: 0808 1645 134 It’s time to think carefully about our future. All our futures. What we do today will have an immeasurable impact on tomorrow. And if we do the right thing, we’ll all benefit. As will the next generation. Superglass may be a brand with 40 years behind it, but our thinking is light years ahead. We create intelligent insulation solutions that enable comfortable living and working environments. And that protect our global environment by saving energy and using recycled glass. A global leader We may still be based in Scotland, but we’re part of global leader in roofing, waterproofing and insulation TECHNONICOL – a business with over 6500 people, 51 manufacturing plants and offices in 79 countries, dedicated to researching and investing in new energy saving solutions to improve the lives of millions of people worldwide. So while insulation is what we make, what we contribute makes an important difference to our planet. www.superglass.co.uk 3 The smartest way to use energy is to not use it at all. That’s the underlying principle behind Superglass thinking. It drives everything we do – from creating new ways of insulating to helping housebuilders make best use of resources. 4 Technical Department: 0808 1645 134 We’ve long been innovators – bringing new ideas, products and thinking to the construction industry.
    [Show full text]
  • Bose-Einstein Condensation in Quantum Glasses
    Bose-Einstein condensation in quantum glasses Giuseppe Carleo,1 Marco Tarzia,2 and Francesco Zamponi3, 4 1SISSA – Scuola Internazionale Superiore di Studi Avanzati and CNR-INFM DEMOCRITOS – National Simulation Center, via Beirut 2-4, I-34014 Trieste, Italy. 2Laboratoire de Physique Th´eorique de la Mati`ere Condens´ee, Universit´ePierre et Marie Curie-Paris 6, UMR CNRS 7600, 4 place Jussieu, 75252 Paris Cedex 05, France. 3Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544, USA 4Laboratoire de Physique Th´eorique, Ecole Normale Sup´erieure, UMR CNRS 8549, 24 Rue Lhomond, 75231 Paris Cedex 05, France. The role of geometrical frustration in strongly interacting bosonic systems is studied with a com- bined numerical and analytical approach. We demonstrate the existence of a novel quantum phase featuring both Bose-Einstein condensation and spin-glass behaviour. The differences between such a phase and the otherwise insulating “Bose glasses” are elucidated. Introduction. Quantum particles moving in a disor- frustrated magnets [10], valence-bond glasses [11] and dered environment exhibit a plethora of non-trivial phe- the order-by-disorder mechanism inducing supersolidity nomena. The competition between disorder and quan- on frustrated lattices [12]. Another prominent manifes- tum fluctuations has been the subject of vast literature tation of frustration is the presence of a large number [1, 2] in past years, with a renewed interest following of metastable states that constitutes the fingerprint of from the exciting frontiers opened by the experimental spin-glasses. When quantum fluctuations and geomet- research with cold-atoms [3, 4]. One of the most striking rical frustration meet, their interplay raises nontrivial features resulting from the presence of a disordered ex- questions on the possible realisation of relevant phases ternal potential is the appearance of localized states [1].
    [Show full text]
  • Quantum Fluctuations Can Promote Or Inhibit Glass Formation
    LETTERS PUBLISHED ONLINE: 9 JANUARY 2011 | DOI: 10.1038/NPHYS1865 Quantum fluctuations can promote or inhibit glass formation Thomas E. Markland1, Joseph A. Morrone1, Bruce J. Berne1, Kunimasa Miyazaki2, Eran Rabani3* and David R. Reichman1* Glasses are dynamically arrested states of matter that do not 0.7 1–4 exhibit the long-range periodic structure of crystals . Here Glass 0.7 we develop new insights from theory and simulation into the 0.6 impact of quantum fluctuations on glass formation. As intuition may suggest, we observe that large quantum fluctuations serve 0.6 φ 0.5 to inhibit glass formation as tunnelling and zero-point energy 0.4 allow particles to traverse barriers facilitating movement. 0.3 However, as the classical limit is approached a regime is 10¬2 10¬1 100 φ 0.5 observed in which quantum effects slow down relaxation Λ∗ making the quantum system more glassy than the classical system. This dynamical ‘reentrance’ occurs in the absence of obvious structural changes and has no counterpart in the phenomenology of classical glass-forming systems. 0.4 Although a wide variety of glassy systems ranging from metallic to colloidal can be accurately described using classical theory, Liquid quantum systems ranging from molecular, to electronic and 5,6 0.3 magnetic form glassy states . Perhaps the most intriguing of these 10¬2 10¬1 100 is the coexistence of superfluidity and dynamical arrest, namely Λ∗ the `superglass' state suggested by recent numerical, theoretical and experimental work7–9. Although such intriguing examples exist, Figure 1 j Dynamic phase diagram calculated from the QMCT for a at present there is no unifying framework to treat the interplay hard-sphere fluid.
    [Show full text]
  • Bose-Einstein Condensation in Quantum Glasses
    Motivations The quantum cavity method A lattice model for the superglass Discussion Conclusions Bose-Einstein condensation in Quantum Glasses Giuseppe Carleo, Marco Tarzia, and Francesco Zamponi∗ Phys. Rev. Lett. 103, 215302 (2009) Collaborators: Florent Krzakala, Laura Foini, Alberto Rosso, Guilhem Semerjian ∗Laboratoire de Physique Th´eorique, Ecole Normale Sup´erieure, 24 Rue Lhomond, 75231 Paris Cedex 05 March 29, 2010 Motivations The quantum cavity method A lattice model for the superglass Discussion Conclusions Outline 1 Motivations Supersolidity of He4 Helium 4: Monte Carlo results 2 The quantum cavity method Regular lattices, Bethe lattices and random graphs Recursion relations Bose-Hubbard models on the Bethe lattice 3 A lattice model for the superglass Extended Hubbard model on a random graph Results A variational argument 4 Discussion Disordered Bose-Hubbard model: the Bose glass 3D spin glass model with quenched disorder Quantum Biroli-M´ezard model: a lattice glass model 5 Conclusions Motivations The quantum cavity method A lattice model for the superglass Discussion Conclusions Outline 1 Motivations Supersolidity of He4 Helium 4: Monte Carlo results 2 The quantum cavity method Regular lattices, Bethe lattices and random graphs Recursion relations Bose-Hubbard models on the Bethe lattice 3 A lattice model for the superglass Extended Hubbard model on a random graph Results A variational argument 4 Discussion Disordered Bose-Hubbard model: the Bose glass 3D spin glass model with quenched disorder Quantum Biroli-M´ezard model: a lattice glass model 5 Conclusions Experimental Results Discovery by Kim & Chan in He4 (Nature & Science 2004). Motivations• The quantumExperimental cavity method A lattice modelResults for the superglass Discussion Conclusions Reproduced after by many4 other groups.
    [Show full text]
  • Quantum Spin Glasses on the Bethe Lattice
    Introduction AKLT states on the Bethe lattice A lattice model with a superglass phase Conclusions Quantum Spin Glasses on the Bethe lattice Francesco Zamponi∗ with C.R.Laumann, S. A. Parameswaran, S.L.Sondhi, PRB 81, 174204 (2010) with G.Carleo and M.Tarzia, PRL 103, 215302 (2009) ∗Laboratoire de Physique Th´eorique, Ecole Normale Sup´erieure, 24 Rue Lhomond, 75231 Paris Cedex 05 June 2, 2010 Introduction AKLT states on the Bethe lattice A lattice model with a superglass phase Conclusions Outline 1 Introduction Classical spin glasses Random lattices and the cavity method Ising antiferromagnet on a random graph 2 AKLT states on the Bethe lattice AKLT states: mapping on a classical model AKLT models on the tree AKLT models on the random graph Phase diagram Spectrum of the quantum spin glass phase 3 A lattice model with a superglass phase Extended Hubbard model on a random graph Results A variational argument 4 Conclusions Introduction AKLT states on the Bethe lattice A lattice model with a superglass phase Conclusions Outline 1 Introduction Classical spin glasses Random lattices and the cavity method Ising antiferromagnet on a random graph 2 AKLT states on the Bethe lattice AKLT states: mapping on a classical model AKLT models on the tree AKLT models on the random graph Phase diagram Spectrum of the quantum spin glass phase 3 A lattice model with a superglass phase Extended Hubbard model on a random graph Results A variational argument 4 Conclusions Introduction AKLT states on the Bethe lattice A lattice model with a superglass phase Conclusions
    [Show full text]
  • Phys. Rev. B 85, 104205 (2012)
    PHYSICAL REVIEW B 85, 104205 (2012) Mean field theory of superglasses Xiaoquan Yu International School for Advanced Studies (SISSA), via Bonomea 265, 34136 Trieste, Italy Markus Muller¨ The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy (Received 5 December 2011; published 19 March 2012) We study the interplay of superfluidity and glassy ordering of hard core bosons with random, frustrating interactions. This is motivated by bosonic systems such as amorphous supersolid, disordered superconductors with preformed pairs, and helium in porous media. We analyze the fully connected mean field version of this problem, which exhibits three low-temperature phases, separated by two continuous phase transitions: an insulating, glassy phase with an amorphous frozen density pattern, a nonglassy superfluid phase, and an intermediate phase, in which both types of order coexist. We elucidate the nature of the phase transitions, highlighting in particular the role of glassy correlations across the superfluid-insulator transition. The latter suppress superfluidity down to T = 0, due to the depletion of the low-energy density of states, unlike in the standard BCS scenario. Further, we investigate the properties of the coexistence (superglass) phase. We find anticorrelations between the local order parameters and a nonmonotonous superfluid order parameter as a function of T . The latter arises due to the weakening of the glassy correlation gap with increasing temperature. Implications of the mean field phenomenology for finite dimensional bosonic glasses with frustrating Coulomb interactions are discussed. DOI: 10.1103/PhysRevB.85.104205 PACS number(s): 61.43.−j, 67.25.dj I. INTRODUCTION presence of slow relaxation and out-of-equilibrium phenomena due to frustrated interactions.
    [Show full text]
  • Evidence for a Superglass State in Solid 4He
    Evidence for a Superglass State in Solid 4He B. Hunt,1§ E. Pratt,1§ V. Gadagkar,1 M. Yamashita,1,2 A. V. Balatsky3 and J.C. Davis1,4 1 Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA. 2 Department of Physics, Kyoto University, Kyoto 606-8502, Japan. 3 T-Division, Center for Integrated Nanotechnologies, MS B 262, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. 4 Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, Scotland, UK. §These authors contributed equally to this work. Science 324, 632 (1 May 2009) Although solid helium-4 (4He) may be a supersolid it also exhibits many phenomena unexpected in that context. We studied relaxation dynamics in the resonance frequency f(T) and dissipation D(T) of a torsional oscillator containing solid 4He. With the appearance of the “supersolid” state, the relaxation times within f(T) and D(T) began to increase rapidly together. More importantly, the relaxation processes in both D(T) and a component of f(T) exhibited a complex synchronized ultra-slow evolution towards equilibrium. Analysis using a generalized rotational susceptibility revealed that, while exhibiting these apparently glassy dynamics, the phenomena were quantitatively inconsistent with a simple excitation freeze-out transition because the variation in f was far too large. One possibility is that amorphous solid 4He represents a new form of supersolid in which dynamical excitations within the solid control the superfluid phase stiffness. A ‘classic’ supersolid (1-5) is a bosonic crystal with an interpenetrating superfluid component.
    [Show full text]
  • Solid He4: a Case Study in Supersolidity
    Solid He4: A Case Study in Supersolidity Raymond Clay December 15, 2011 Abstract Solid He4 currently is the strongest candidate for realizing the proposed supersolid state of matter. Recent experimental results, however, have served to signicantly complicate the original picture of solid He4 as a supersolid. In an attempt to get a handle on what has turned out to be a broad and rapidly changing eld, I will present the original theoretical understanding as laid out by Andreev and Lifshitz, Chester, and Leggett, summarize the experimental data since Kim and Chan's discovery of non-classical rotational inertia, and then describe how modern theoretical work has developed to accommodate some unusual discoveries. 1 1 Historical Introduction The existence and general properties of a supersolid state of matter were proposed about forty years ago, generally credited to Andreev and Lifshitz' paper in 1969, and to Chester's in 1970[1, 2]. In it, they proposed a novel phase of matter in which a system, while ostensibly solid, could also exhibit superuid phenomenon due to quantum eects. Though the superuid state had been realized before in He4, this supersolid state represented an entirely dierent beast. Understandably, quite a bit of excitement was generated in 2004 when Kim and Chan observed non-classical rotational inertia in solid He4 (a necessary condition for supersolidity), and so the hunt began to characterize this novel state and understand its underlying mechanism. The enthusiasm is justied, as solid He4 seems to be the only possible realization of a supersolid state at this time, although such a state could be produced in optical lattices [17].
    [Show full text]
  • Arxiv:0807.2458V2
    Theory of the superglass phase Giulio Biroli,1 Claudio Chamon,2 and Francesco Zamponi3 1Institut de Physique Th´eorique, CEA, IPhT, F-91191 Gif-sur-Yvette, France CNRS, URA 2306, F-91191 Gif-sur-Yvette, France 2Physics Department, Boston University, Boston, MA 02215, USA 3CNRS-UMR 8549, Laboratoire de Physique Th´eorique, Ecole´ Normale Sup´erieure, 24 Rue Lhomond, 75231 Paris Cedex 05, France (Dated: November 3, 2018) A superglass is a phase of matter which is characterized at the same time by superfluidity and a frozen amorphous structure. We introduce a model of interacting bosons in three dimensions that displays this phase unambiguously and that can be analyzed exactly or using controlled approxima- tions. Employing a mapping between quantum Hamiltonians and classical Fokker-Planck operators, we show that the ground state wavefunction of the quantum model is proportional to the Boltzmann measure of classical hard spheres. This connection allows us to obtain quantitative results on static and dynamic quantum correlation functions. In particular, by translating known results on the glassy dynamics of Brownian hard spheres we work out the properties of the superglass phase and of the quantum phase transition between the superfluid and the superglass phase. I. INTRODUCTION Solids do not flow. This apparently tautological statement can be wrong in two ways. First, solidity is in general a timescale-dependent phenomenon. Crystal or glasses, well known solids on most experimentally relevant timescales, do flow if one waits long enough (see Ref. 1 for example). Second, at very small temperatures, quantum solids may become superfluids as suggested theoretically in the early seventies2–4.
    [Show full text]
  • Saga of Superfluid Solids
    Review Saga of Superfluid Solids Vyacheslav I. Yukalov 1,2 1 Bogolubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia; yukalovtheor.jinr.ru 2 Instituto de Fisica de São Carlos, Universidade de São Paulo, CP 369, São Carlos, São Paulo 13560-970, Brazil Received: 12 November 2019; Accepted: 3 February 2020; Published: 7 February 2020 Abstract: The article presents the state of the art and reviews the literature on the long-standing problem of the possibility for a sample to be at the same time solid and superfluid. Theoretical models, numerical simulations, and experimental results are discussed. Keywords: solid state; superfluid state; diagonal order; off-diagonal order; translational symmetry; global gauge symmetry 1. Introduction The term “superfluidity” was coined by Kapitza, who actually discovered the phenomenon of superfluidity in liquid Helium, in his paper [1] followed by the paper by Allen and Misener [2]. Kapitza had set up an experiment with two cylinders that were connected by a thin tube. Only below the l point, helium was flowing easily through the tube, suggesting a strikingly low viscosity. The first explanation of superfluidity, in the frame of the two-fluid model, was suggested by Landau [3–5] and Tisza [6]. The key evidence establishing the two-fluid model of superfluidity was given by Andronikashvili [7–9] studying the period and damping of torsional oscillations of stacked closely spaced rotating disks. More details about the interesting history concerning the discovery of and first works on superfluidity can be found in Refs. [10–13]. However, the subject of this review is not the description of superfluidity in liquids, but a rather unexpected problem considering the possibility of superfluid effects in solids.
    [Show full text]
  • Superglass Phase of 4He M Boninsegni
    University of Massachusetts Amherst ScholarWorks@UMass Amherst Physics Department Faculty Publication Series Physics 2006 Superglass Phase of 4He M Boninsegni Nikolai Prokof 'ev University of Massachusetts - Amherst, [email protected] Boris Svistunov University of Massachusetts - Amherst, [email protected] Follow this and additional works at: https://scholarworks.umass.edu/physics_faculty_pubs Part of the Physics Commons Recommended Citation Boninsegni, M; Prokof'ev, Nikolai; and Svistunov, Boris, "Superglass Phase of 4He" (2006). Physics Review Letters. 1151. Retrieved from https://scholarworks.umass.edu/physics_faculty_pubs/1151 This Article is brought to you for free and open access by the Physics at ScholarWorks@UMass Amherst. It has been accepted for inclusion in Physics Department Faculty Publication Series by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. Superglass Phase of 4He Massimo Boninsegni1, Nikolay Prokof’ev2,3,4, and Boris Svistunov2,3 1Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 2Department of Physics, University of Massachusetts, Amherst, MA 01003 3Russian Research Center “Kurchatov Institute”, 123182 Moscow 4Department of Physics, Cornell University, Ithaca, NY 14850 (Dated: February 2, 2008) We study different solid phases of 4He, by means of Path Integral Monte Carlo simulations based on a recently developed worm algorithm. Our study includes simulations that start off from a high-T gas phase, which is then “quenched” down to T =0.2 K. The low-T properties of the system crucially depend on the initial state. While an ideal hcp crystal is a clear-cut insulator, the disordered system freezes into a superglass, i.e., a metastable amorphous solid featuring off-diagonal long-range order and superfluidity.
    [Show full text]