Superfluid Theory
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Φ0-Magnetic Force Microscopy for Imaging and Control of Vortex
Imaging and controlling vortex dynamics in mesoscopic superconductor-normal-metal-superconductor arrays Tyler R. Naibert1, Hryhoriy Polshyn1,2,*, Rita Garrido-Menacho1, Malcolm Durkin1, Brian Wolin1, Victor Chua1, Ian Mondragon-Shem1, Taylor Hughes1, Nadya Mason1,*, and Raffi Budakian1,3 1Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green St., Urbana, IL 61801-3080, USA 2Department of Physics, University of California, Santa Barbara, CA 93106, USA 3Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L3G1 Department of Physics, University of Waterloo, Waterloo, ON, Canada, N2L3G1 Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada, N2L2Y5 Canadian Institute for Advanced Research, Toronto, ON, Canada, M5G1Z8 *Corresponding authors. Email: [email protected]; [email protected] Harnessing the properties of vortices in superconductors is crucial for fundamental science and technological applications; thus, it has been an ongoing goal to locally probe and control vortices. Here, we use a scanning probe technique that enables studies of vortex dynamics in superconducting systems by leveraging the resonant behavior of a raster-scanned, magnetic-tipped cantilever. This experimental setup allows us to image and control vortices, as well as extract key energy scales of the vortex interactions. Applying this technique to lattices of superconductor island arrays on a metal, we obtain a variety of striking spatial patterns that encode information about the energy landscape for vortices in the system. We interpret these patterns in terms of local vortex dynamics and extract the relative strengths of the characteristic energy scales in the system, such as the vortex-magnetic field and vortex-vortex interaction strengths, as well as the vortex chemical potential. -
Scanning Hall Probe Microscopy of Vortex Matter in Single-And Two-Gap Superconductors
ARENBERG DOCTORAL SCHOOL Faculty of Science Scanning Hall probe microscopy of vortex matter in single-and two-gap superconductors - Bart Raes Promotors: Dissertation presented in partial Prof.Dr. Victor V. Moshchalkov fulfillment of the requirements for the Prof.Dr. Jacques Tempère PhD degree July 2013 Scanning Hall probe microscopy of vortex matter in single-and two-gap superconductors Bart RAES Dissertation presented in partial fulfillment of the requirements for the PhD degree Members of the Examination committee: Prof. Dr. Victor V. Moshchalkov KU Leuven (Promotor) Prof. Dr. Jacques Tempère Universiteit Antwerpen (Co-promotor) Prof. Dr. J. Van de Vondel KU Leuven (Secretary) Prof. Dr. L. Chibotaru KU Leuven (President) Prof. Dr. J. Vanacken KU Leuven Dr. J. Gutierrez Royo KU Leuven Prof. Dr. A.V. Silhanek Université de Liège Prof. Dr. S. Bending University of Bath Prof. Dr. G. Borghs KU Leuven, IMEC July 2013 © 2013 KU Leuven, Groep Wetenschap & Technologie, Arenberg Doctoraatsschool, W. de Croylaan 6, 3001 Leuven, België Alle rechten voorbehouden. Niets uit deze uitgave mag worden vermenigvuldigd en/of openbaar gemaakt worden door middel van druk, fotocopie, microfilm, elektronisch of op welke andere wijze ook zonder voorafgaande schriftelijke toestemming van de uitgever. All rights reserved. No part of the publication may be reproduced in any form by print, photoprint, microfilm or any other means without written permission from the publisher. ISBN 978-90-8649-638-9 D/2013/10.705/53 Dankwoord-Acknowledgements Doctoreren is niet alleen het resultaat van bijna vier jaar wetenschappelijk onderzoek, het is een lange weg met veel hindernissen maar zeker ook enkele hoogtepunten. -
Fermionic Condensation in Ultracold Atoms, Nuclear Matter and Neutron Stars
Journal of Physics: Conference Series OPEN ACCESS Related content - Condensate fraction of asymmetric three- Fermionic condensation in ultracold atoms, component Fermi gas Du Jia-Jia, Liang Jun-Jun and Liang Jiu- nuclear matter and neutron stars Qing - S-Wave Scattering Properties for Na—K Cold Collisions To cite this article: Luca Salasnich 2014 J. Phys.: Conf. Ser. 497 012026 Zhang Ji-Cai, Zhu Zun-Lue, Sun Jin-Feng et al. - Landau damping in a dipolar Bose–Fermi mixture in the Bose–Einstein condensation (BEC) limit View the article online for updates and enhancements. S M Moniri, H Yavari and E Darsheshdar This content was downloaded from IP address 170.106.40.139 on 26/09/2021 at 20:46 22nd International Laser Physics Worksop (LPHYS 13) IOP Publishing Journal of Physics: Conference Series 497 (2014) 012026 doi:10.1088/1742-6596/497/1/012026 Fermionic condensation in ultracold atoms, nuclear matter and neutron stars Luca Salasnich Dipartimento di Fisica e Astronomia “Galileo Galilei” and CNISM, Universit`a di Padova, Via Marzolo 8, 35131 Padova, Italy E-mail: [email protected] Abstract. We investigate the Bose-Einstein condensation of fermionic pairs in three different superfluid systems: ultracold and dilute atomic gases, bulk neutron matter, and neutron stars. In the case of dilute gases made of fermionic atoms the average distance between atoms is much larger than the effective radius of the inter-atomic potential. Here the condensation of fermionic pairs is analyzed as a function of the s-wave scattering length, which can be tuned in experiments by using the technique of Feshbach resonances from a small and negative value (corresponding to the Bardeen-Cooper-Schrieffer (BCS) regime of Cooper Fermi pairs) to a small and positive value (corresponding to the regime of the Bose-Einstein condensate (BEC) of molecular dimers), crossing the unitarity regime where the scattering length diverges. -
Realization of Bose-Einstein Condensation in Dilute Gases
Realization of Bose-Einstein Condensation in dilute gases Guang Bian May 3, 2008 Abstract: This essay describes theoretical aspects of Bose-Einstein Condensation and the first experimental realization of BEC in dilute alkali gases. In addition, some recent experimental progress related to BEC are reported. 1 Introduction A Bose–Einstein condensate is a state of matter of bosons confined in an external potential and cooled to temperatures very near to absolute zero. Under such supercooled conditions, a large fraction of the atoms collapse into the lowest quantum state of the external potential, at which point quantum effects become apparent on a macroscopic scale. When a bosonic system is cooled below the critical temperature of Bose-Einstein condensation, the behavior of the system will change dramatically, because the condensed particles behaving like a single quantum entity. In this section, I will review the early history of Bose- Einstein Condensation. In 1924, the Indian physicist Satyendra Nath Bose proposed a new derivation of the Planck radiation law. In his derivation, he found that the indistinguishability of particle was the key point to reach the radiation law and he for the first time took the position that the Maxwell-Boltzmann distribution would not be true for microscopic particles where fluctuations due to Heisenberg's uncertainty principle will be significant. In the following year Einstein generalized Bose’s method to ideal gases and he showed that the quantum gas would undergo a phase transition at a sufficiently low temperature when a large fraction of the atoms would condense into the lowest energy state. At that time Einstein doubted the strange nature of his prediction and he wrote to Ehrenfest the following sentences, ‘From a certain temperature on, the molecules “condense” without attractive forces, that is, they accumulate at zero velocity. -
LESSONS from TOPOLOGICAL SUPERFLUIDS: SAFE and DANGEROUS ROUTES to ANTISPACETIME 1 1 1,2 Llv.B
FEATURES LESSONS FROM TOPOLOGICAL SUPERFLUIDS: SAFE AND DANGEROUS ROUTES TO ANTISPACETIME 1 1 1,2 l V.B. Eltsov , J. Nissinen and G.E. Volovik – DOI: https://doi.org/10.1051/epn/2019504 l 1 Low Temperature Laboratory, Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland l 2 Landau Institute for Theoretical Physics, acad. Semyonov av., 1a, 142432, Chernogolovka, Russia All realistic second order phase transitions are undergone at finite transition rate and are therefore non-adiabatic. In symmetry-breaking phase transitions the non-adiabatic processes, as predicted by Kibble and Zurek [1, 2], lead to the formation of topological defects (the so-called Kibble-Zurek mechanism). The exact nature of the resulting defects depends on the detailed symmetry-breaking pattern. or example, our universe – the largest condensed topological and nontopological objects (skyrmions and matter system known to us – has undergone Q-balls), etc. several symmetry-breaking phase transitions The model predictions can be tested in particle accel- Fafter the Big Bang. As a consequence, a variety erators (now probing energy densities >10-12s after the of topological defects might have formed during the early Big Bang) and in cosmological observations (which have evolution of the Universe. Depending on the Grand Uni- not yet identified such defects to date). The same physics, fied Theory model, a number of diffierent cosmic -topo however, can be probed in symmetry breaking transitions logical defects have been predicted to exist. Among them in condensed matter systems — in fermionic superfluid are point defects, such as the 't Hooft-Polyakov magnetic 3He to an astonishing degree of similarity. -
Twist Effects on Quantum Vortex Defects
Journal of Physics: Conference Series PAPER • OPEN ACCESS Twist effects on quantum vortex defects To cite this article: M Foresti 2021 J. Phys.: Conf. Ser. 1730 012016 View the article online for updates and enhancements. This content was downloaded from IP address 170.106.40.40 on 26/09/2021 at 14:31 IC-MSQUARE 2020 IOP Publishing Journal of Physics: Conference Series 1730 (2021) 012016 doi:10.1088/1742-6596/1730/1/012016 Twist effects on quantum vortex defects M Foresti Department of Mathematics & Applications, University of Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy E-mail: [email protected] Abstract. We demonstrate that on a quantum vortex in Bose-Einstein condensates can form a new, central phase singularity. We define the twist phase for isophase surfaces and show that if the injection of a twist phase is global this phenomenon is given by an analog of the Aharonov- Bohm effect. We show analytically that the injection of a twist phase makes the filament unstable, that is the GP equation is modified by a new term that makes the Hamiltonian non-Hermitian. Using Kleinert's theory for multi-valued fields we show that this instability is compensated by the creation of the second vortex, possibly linked with the first one. 1. Introduction A Bose-Einstein condensate (BEC) is a diluted gas of bosons at very low temperature (see [1] and [2]) described by a unique scalar, complex-valued field = (x; t) called order parameter, that depends on position x and time t. The equation that describes the dynamics of a BEC is the Gross-Pitaevskii equation (GPE) written here in a non-dimensional [3]: i i @ = r2 + 1 − j j2 : (1) t 2 2 This is a type of non-linear Scrh¨odingerequation in three-dimensional space. -
States of Matter Part I
States of Matter Part I. The Three Common States: Solid, Liquid and Gas David Tin Win Faculty of Science and Technology, Assumption University Bangkok, Thailand Abstract There are three basic states of matter that can be identified: solid, liquid, and gas. Solids, being compact with very restricted movement, have definite shapes and volumes; liquids, with less compact makeup have definite volumes, take the shape of the containers; and gases, composed of loose particles, have volumes and shapes that depend on the container. This paper is in two parts. A short description of the common states (solid, liquid and gas) is described in Part I. This is followed by a general observation of three additional states (plasma, Bose-Einstein Condensate, and Fermionic Condensate) in Part II. Keywords: Ionic solids, liquid crystals, London forces, metallic solids, molecular solids, network solids, quasicrystals. Introduction out everywhere within the container. Gases can be compressed easily and they have undefined shapes. This paper is in two parts. The common It is well known that heating will cause or usual states of matter: solid, liquid and gas substances to change state - state conversion, in or vapor1, are mentioned in Part I; and the three accordance with their enthalpies of fusion ∆H additional states: plasma, Bose-Einstein f condensate (BEC), and Fermionic condensate or vaporization ∆Hv, or latent heats of fusion are described in Part II. and vaporization. For example, ice will be Solid formation occurs when the converted to water (fusion) and thence to vapor attraction between individual particles (atoms (vaporization). What happens if a gas is super- or molecules) is greater than the particle energy heated to very high temperatures? What happens (mainly kinetic energy or heat) causing them to if it is cooled to near absolute zero temperatures? move apart. -
Generation and Detection of Continuous Variable Quantum Vortex States Via Compact Photonic Devices
hv photonics Article Generation and Detection of Continuous Variable Quantum Vortex States via Compact Photonic Devices David Barral *, Daniel Balado and Jesús Liñares Optics Area, Department of Applied Physics, Faculty of Physics and Faculty of Optics and Optometry, University of Santiago de Compostela, Campus Vida s/n (Campus Universitario Sur), Santiago de Compostela, Galicia E-15782, Spain; [email protected] (D.B.); [email protected] (J.L.) * Correspondence: [email protected]; Tel.: +34-881-811-000 Received: 10 October 2016; Accepted: 29 December 2016; Published: 3 January 2017 Abstract: A quantum photonic circuit with the ability to produce continuous variable quantum vortex states is proposed. This device produces two single-mode squeezed states which go through a Mach-Zehnder interferometer where photons are subtracted by means of weakly coupled directional couplers towards ancillary waveguides. The detection of a number of photons in these modes heralds the production of a quantum vortex. Likewise, a measurement system of the order and handedness of quantum vortices is introduced and the performance of both devices is analyzed in a realistic scenario by means of the Wigner function. These devices open the possibility of using the quantum vortices as carriers of quantum information. Keywords: quantum information processing; continuous variables; integrated optics 1. Introduction In recent years, there has been an increasing interest in the processing of quantum information (QIP) with continuous variables (CV-QIP) [1]. CV-QIP protocols are based on Gaussian states as resources of entanglement. However, the use of non-Gaussian states has been shown to be essential in certain quantum protocols, like the entanglement distillation [2–5]. -
A Vortex Formulation of Quantum Physics Setting Discrete Quantum States Into Continuous Space-Time
Fred Y. Ye, IJNSR, 2017; 1:4 Research Article IJNSR (2017) 1:4 International Journal of Natural Science and Reviews (ISSN:2576-5086) A Vortex Formulation of Quantum Physics Setting Discrete Quantum States into Continuous Space-time Fred Y. Ye 1, 2* 1 School of Information Management, Nanjing University, Nanjing 210023, CHINA 2International Joint Informatics Laboratory (IJIL), UI-NU, Champaign-Nanjing ABSTRACT Any quantum state can be described by a vortex, which is math- *Correspondence to Author: ematically a multi-vector and physically a united-measure. Fred Y. Ye When the vortex formulation of quantum physics is introduced, School of Information Management, Hamil-ton principle keeps its core position in physical analysis. Nanjing University, Nanjing 210023, While the global characteristics are described by Lagranrian CHINA; International Joint Informat- function for dynamics and double complex core function for ics Laboratory (IJIL), UI-NU, Cham- stable states, Schrödinger equation and gauge symmetries paign-Nanjing reveal local char-acteristics. The vortex-based physics provides a new unified understanding of wave-particle duality and uncertainty, quantum entanglement and teleportation, as How to cite this article: well as quantum information and computation, with setting Fred Y. Ye. A Vortex Formulation of discrete quantum states into con-tinuous space-time for Quantum Physics Setting Discrete keeping concordance of methodology in processing micro- Quantum States into Continuous particle and macro-galaxy. Two fundamental experiments are Space-time. International Journal suggested to correct and verify the physical for-mulation. of Natural Science and Reviews, 2017; 1:4. Keywords: Vortex; vortex formulation; quantum mechanism; quantum state; quantum physics; space-time eSciPub LLC, Houston, TX USA. -
Driving a Strongly Interacting Superfluid out of Equilibrium
Driving a Strongly Interacting Superfluid out of Equilibrium Dissertation zur Erlangung des Doktorgrades (Dr. rer. nat.) der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn von Alexandra Bianca Behrle Bonn, 27.07.2017 Dieser Forschungsbericht wurde als Dissertation von der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Bonn angenommen und ist auf dem Hochschulschriftenserver der ULB Bonn http://hss.ulb.uni-bonn.de/diss_online elektronisch publiziert. 1. Gutachter: Prof. Dr. Michael Köhl 2. Gutachter: Prof. Dr. Stefan Linden Tag der Promotion: 21.12.2017 Erscheinungsjahr: 2018 To my parents and my sister iii "Fortunately science, like that nature to which it belongs, is neither limited by time nor by space. It belongs to the world, and is of no country and no age. The more we know, the more we feel our ignorance; the more we feel how much remains unknown..." -Humphry Davy, the discoverer of the element sodium and the eponym of our experiment. iv Abstract A new field of research, which gained interest in the past years, is the field of non- equilibrium physics of strongly interacting fermionic systems. In this thesis we present a novel apparatus to study an ultracold strongly interacting superfluid Fermi gas driven out of equilibrium. In more detail, we study the excitation of a collective mode, the Higgs mode, and the dynamics occurring after a rapid quench of the interaction strength. Ultracold gases are ideal candidates to explore the physics of strongly inter- acting Fermi gases due to their purity and the possibility to continuously change many different system parameters, such as the interaction strength. -
Physics of Superfluid Helium-4 Vortex Tangles in Normal-Fluid Strain Fields
Physics of superfluid helium-4 vortex tangles in normal-fluid strain fields Demosthenes Kivotides1, Anthony Leonard2 1Strathclyde University, Glasgow, UK 2California Institute of Technology, Pasadena, CA, USA (Dated: March 5, 2021) Abstract By employing dimensional analysis, we scale the equations of the mesoscopic model of finite temperature superfluid hydrodynamics. Based on this scaling, we set up three problems, that depict the effects of kinematic, normal-fluid strain fields on superfluid vortex loops, and characterize small- scale processes in fully developed turbulence. We also develop a formula for the computation of energy spectra corresponding to superfluid vortex tangles in unbounded domains. Employing this formula, we compute energy spectra of superfluid vortex patterns induced by uniaxial, equibiaxial and simple-shear normal-fluid flows. By comparing the steady-state superfluid spectra and vortex structures, we conclude that normal-flow strain fields do not play important role in explaining the phenomenology of fully developed superfluid turbulence. This is in sharp contrast with the role of vortical normal-flow fields in offering plausible, structural explanations of superfluid vortex patterns and spectra entailed in numerical turbulent solutions of the mesoscopic model. 1 INTRODUCTION The advent of quantum theory posed the problem of quantizing fluid dynamics. The most obvious choice, i.e., quantizing the Navier-Stokes fluid, leads to unsurpassable mathematical difficulties with uncontrollable singularities [1]. This could be because Navier-Stokes is a statistical, dissipative field theory and, traditionally, quantum mechanics was successful operating on conservative classical field theories. Indeed, things become better with the quantization of (nonlinear) Schroedinger (NLS) type fluids, that can explain superfluidity via spontaneous breaking of the particle number symmetry which induces a ground state (superfluid) whose topological defects (superfluid vortices) interact with the fluctuations of the quantum field (normal fluid) [2–7]. -
Modeling Quantum Fluid Dynamics at Nonzero Temperatures
Modeling quantum fluid dynamics at SPECIAL FEATURE nonzero temperatures Natalia G. Berloffa,b,1, Marc Brachetc, and Nick P. Proukakisd aDepartment of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom; bCambridge-Skoltech Quantum Fluids Laboratory, Skolkovo Institute of Science and Technology ul. Novaya, Skolkovo 143025, Russian Federation; cCentre National de la Recherche Scientifique, Laboratoire de Physique Statistique, Université Pierre-et-Marie-Curie Paris 06, Université Paris Diderot, Ecole Normale Supérieure, 75231 Paris Cedex 05, France; and dJoint Quantum Centre (JQC) Durham–Newcastle, School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom Edited by Katepalli R. Sreenivasan, New York University, New York, NY, and approved December 13, 2013 (received for review July 15, 2013) The detailed understanding of the intricate dynamics of quantum similar [e.g., Kolmogorov spectrum (9–13)], features sensitive to fluids, in particular in the rapidly growing subfield of quantum the vortex core structure arising at lengthscales smaller than the turbulence which elucidates the evolution of a vortex tangle in average intervortex spacing [e.g., velocity statistics (20–22) and a superfluid, requires an in-depth understanding of the role of finite pressure (23)] show starkly different behavior––see, e.g., the temperature in such systems. The Landau two-fluid model is the most recent reviews (24, 25). In addition to liquid helium (2, 26), there successful hydrodynamical theory of superfluid helium, but by the has been some recent interest in the observation of turbulence in nature of the scale separations it cannot give an adequate descrip- smaller inhomogeneous confined weakly interacting gases (27, tion of the processes involving vortex dynamics and interactions.