1
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Negro G, Carenza LN, Gonnella G, Marenduzzo D, Orlandini E. Topological phases and curvature-driven pattern formation in cholesteric shells. SOFT MATTER 2023; 19:1987-2000. [PMID: 36847796 DOI: 10.1039/d2sm01347a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We study the phase behaviour of cholesteric liquid crystal shells with different geometries. We compare the cases of tangential anchoring and no anchoring at the surface, focussing on the former case, which leads to a competition between the intrinsic tendency of the cholesteric to twist and the anchoring free energy which suppresses it. We then characterise the topological phases arising close to the isotropic-cholesteric transition. These typically consist of quasi-crystalline or amorphous tessellations of the surface by half-skyrmions, which are stable at lower and larger shell sizes, respectively. For ellipsoidal shells, defects in the tessellation couple to a local curvature, and according to the shell size, they either migrate to the poles or distribute uniformly on the surface. For toroidal shells, the variations in the local curvature of the surface stabilise heterogeneous phases where cholesteric or isotropic patterns coexist with hexagonal lattices of half-skyrmions.
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Affiliation(s)
- G Negro
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - L N Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
| | - G Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - E Orlandini
- Dipartimento di Fisica e Astronomia, Università di Padova, 35131 Padova, Italy
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2
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Barresi A, Boulet A, Magierski P, Wlazłowski G. Dissipative Dynamics of Quantum Vortices in Fermionic Superfluid. PHYSICAL REVIEW LETTERS 2023; 130:043001. [PMID: 36763425 DOI: 10.1103/physrevlett.130.043001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/08/2022] [Accepted: 01/05/2023] [Indexed: 06/18/2023]
Abstract
In a recent article, Kwon et al. [Nature (London) 600, 64 (2021)NATUAS0028-083610.1038/s41586-021-04047-4] revealed nonuniversal dissipative dynamics of quantum vortices in a fermionic superfluid. The enhancement of the dissipative process is pronounced for the Bardeen-Cooper-Schrieffer interaction regime, and it was suggested that the effect is due to the presence of quasiparticles localized inside the vortex core. We test this hypothesis through numerical simulations with time-dependent density-functional theory: a fully microscopic framework with fermionic degrees of freedom. The results of fully microscopic calculations expose the impact of the vortex-bound states on dissipative dynamics in a fermionic superfluid. Their contribution is too weak to explain the experimental measurements, and we identify that thermal effects, giving rise to mutual friction between superfluid and the normal component, dominate the observed dynamics.
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Affiliation(s)
- Andrea Barresi
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - Antoine Boulet
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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3
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Wlazłowski G, Xhani K, Tylutki M, Proukakis NP, Magierski P. Dissipation Mechanisms in Fermionic Josephson Junction. PHYSICAL REVIEW LETTERS 2023; 130:023003. [PMID: 36706420 DOI: 10.1103/physrevlett.130.023003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/10/2022] [Accepted: 12/12/2022] [Indexed: 06/18/2023]
Abstract
We characterize numerically the dominant dynamical regimes in a superfluid ultracold fermionic Josephson junction. Beyond the coherent Josephson plasma regime, we discuss the onset and physical mechanism of dissipation due to the superflow exceeding a characteristic speed, and provide clear evidence distinguishing its physical mechanism across the weakly and strongly interacting limits, despite qualitative dynamics of global characteristics being only weakly sensitive to the operating dissipative mechanism. Specifically, dissipation in the strongly interacting regime occurs through the phase-slippage process, caused by the emission and propagation of quantum vortices, and sound waves-similar to the Bose-Einstein condensation limit. Instead, in the weak interaction limit, the main dissipative channel arises through the pair-breaking mechanism.
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Affiliation(s)
- Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Klejdja Xhani
- Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), 50019 Sesto Fiorentino, Italy
| | - Marek Tylutki
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - Nikolaos P Proukakis
- Joint Quantum Centre (JQC) Durham-Newcastle, School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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4
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Liu XP, Yao XC, Deng Y, Wang XQ, Wang YX, Huang CJ, Li X, Chen YA, Pan JW. Universal Dynamical Scaling of Quasi-Two-Dimensional Vortices in a Strongly Interacting Fermionic Superfluid. PHYSICAL REVIEW LETTERS 2021; 126:185302. [PMID: 34018783 DOI: 10.1103/physrevlett.126.185302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 09/02/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Vortices play a leading role in many fascinating quantum phenomena. Here we generate a large number of vortices by thermally quenching a fermionic superfluid of ^{6}Li atoms in an oblate optical trap and study their annihilation dynamics and spatial distribution. Over a wide interaction range from the attractive to the repulsive side across the Feshbach resonance, these quasi-two-dimensional vortices are observed to follow algebraic scaling laws both in time and space, having exponents consistent with the two-dimensional universality. We further simulate the classical XY model on the square lattice by a Glauber dynamics and find good agreement between the numerical and experimental behaviors. Our work provides a direct demonstration of the universal 2D vortex dynamics.
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Affiliation(s)
- Xiang-Pei Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Xing-Can Yao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Youjin Deng
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
- MinJiang Collaborative Center for Theoretical Physics, College of Physics and Electronic Information Engineering, Minjiang University, Fuzhou 350108, China
| | - Xiao-Qiong Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Yu-Xuan Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Chun-Jiong Huang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Xiaopeng Li
- State Key Laboratory of Surface Physics, Institute of Nanoelectronics and Quantum Computing,and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Yu-Ao Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- Shanghai Branch, CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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5
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Manzetti S, Trounev A. Analytical Solutions for a Supersymmetric Wave‐Equation for Quasiparticles in a Quantum System. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sergio Manzetti
- Uppsala UniversityBMC, Dept Mol. Cell Biol, Box 596 SE‐75124 Uppsala Sweden
- Fjordforsk A/S Midtun 6894 Vangsnes Norway
| | - Alexander Trounev
- Fjordforsk A/S Midtun 6894 Vangsnes Norway
- A & E Trounev IT Consulting 60005 Toronto Canada
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6
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Park JW, Ko B, Shin Y. Critical Vortex Shedding in a Strongly Interacting Fermionic Superfluid. PHYSICAL REVIEW LETTERS 2018; 121:225301. [PMID: 30547641 DOI: 10.1103/physrevlett.121.225301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 06/09/2023]
Abstract
We study the critical vortex shedding in a strongly interacting fermionic superfluid of ^{6}Li across the BEC-BCS crossover. By moving an optical obstacle in the sample and directly imaging the vortices after the time of flight, the critical velocity u_{vor} for vortex shedding is measured as a function of the obstacle travel distance L. The observed u_{vor} increases with decreasing L, where the rate of increase is the highest in the unitary regime. In the deep Bose-Einstein condensation regime, an empirical dissipation model well captures the dependence of u_{vor} on L, characterized by a constant value of η=-[d(1/u_{vor})/d(1/L)]. However, as the system is tuned across the resonance, a step increase of η develops about a characteristic distance L_{c} as L is increased, where L_{c} is comparable to the obstacle size. This bimodal behavior is strengthened as the system is tuned towards the BCS regime. We attribute this evolution of u_{vor} to the emergence of the underlying fermionic degree of freedom in the vortex-shedding dynamics of a Fermi condensate.
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Affiliation(s)
- Jee Woo Park
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Bumsuk Ko
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea
| | - Y Shin
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea
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7
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Wlazłowski G, Sekizawa K, Marchwiany M, Magierski P. Suppressed Solitonic Cascade in Spin-Imbalanced Superfluid Fermi Gas. PHYSICAL REVIEW LETTERS 2018; 120:253002. [PMID: 29979062 DOI: 10.1103/physrevlett.120.253002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Indexed: 06/08/2023]
Abstract
Cold atoms experiments offer invaluable information on superfluid dynamics, including decay cascades of topological defects. While the cascade properties are well established for Bose systems, our understanding of their behavior in Fermi counterparts is very limited, in particular in spin-imbalanced systems, where superfluid (paired) and normal (unpaired) particles naturally coexist giving rise to complex spatial structure of the atomic cloud. Here we show, based on a newly developed microscopic approach, that the decay cascades of topological defects are dramatically modified by the spin polarization. We demonstrate that decay cascades end up at different stages: "dark soliton," "vortex ring," or "vortex line," depending on the polarization. We reveal that it is caused by sucking of unpaired particles into the soliton's internal structure. As a consequence vortex reconnections are hindered and we anticipate that quantum turbulence phenomenon can be significantly affected, indicating new physics induced by polarization effects.
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Affiliation(s)
- Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, Warsaw 00-662, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Kazuyuki Sekizawa
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, Warsaw 00-662, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Maciej Marchwiany
- Interdisciplinary Centre for Mathematical and Computational Modelling (ICM), University of Warsaw, A. Pawińskiego 5a, Warsaw 02-106, Poland
| | - Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, Warsaw 00-662, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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8
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Josephson vortex loops in nanostructured Josephson junctions. Sci Rep 2018; 8:2733. [PMID: 29426843 PMCID: PMC5807441 DOI: 10.1038/s41598-018-21015-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/23/2018] [Indexed: 11/08/2022] Open
Abstract
Linked and knotted vortex loops have recently received a revival of interest. Such three-dimensional topological entities have been observed in both classical- and super-fluids, as well as in optical systems. In superconductors, they remained obscure due to their instability against collapse - unless supported by inhomogeneous magnetic field. Here we reveal a new kind of vortex matter in superconductors - the Josephson vortex loops - formed and stabilized in planar junctions or layered superconductors as a result of nontrivial cutting and recombination of Josephson vortices around the barriers for their motion. Engineering latter barriers opens broad perspectives on loop manipulation and control of other possible knotted/linked/entangled vortex topologies in nanostructured superconductors. In the context of Josephson devices proposed to date, the high-frequency excitations of the Josephson loops can be utilized in future design of powerful emitters, tunable filters and waveguides of high-frequency electromagnetic radiation, thereby pushing forward the much needed Terahertz technology.
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9
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Sekizawa K, Wlazłowski G, Magierski P. Solitonic excitations in collisions of superfluid nuclei a qualitatively new phenomenon distinct from the Josephson effect. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Geng Z, Zhang X, Fan Z, Lv X, Su Y, Chen H. Recent Progress in Optical Biosensors Based on Smartphone Platforms. SENSORS 2017; 17:s17112449. [PMID: 29068375 PMCID: PMC5713127 DOI: 10.3390/s17112449] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 02/07/2023]
Abstract
With a rapid improvement of smartphone hardware and software, especially complementary metal oxide semiconductor (CMOS) cameras, many optical biosensors based on smartphone platforms have been presented, which have pushed the development of the point-of-care testing (POCT). Imaging-based and spectrometry-based detection techniques have been widely explored via different approaches. Combined with the smartphone, imaging-based and spectrometry-based methods are currently used to investigate a wide range of molecular properties in chemical and biological science for biosensing and diagnostics. Imaging techniques based on smartphone-based microscopes are utilized to capture microscale analysts, while spectrometry-based techniques are used to probe reactions or changes of molecules. Here, we critically review the most recent progress in imaging-based and spectrometry-based smartphone-integrated platforms that have been developed for chemical experiments and biological diagnosis. We focus on the analytical performance and the complexity for implementation of the platforms.
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Affiliation(s)
- Zhaoxin Geng
- School of Information Engineering, Minzu University of China, Beijing 100081, China.
| | - Xiong Zhang
- School of Information Engineering, Minzu University of China, Beijing 100081, China.
| | - Zhiyuan Fan
- State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Xiaoqing Lv
- State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Yue Su
- State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Hongda Chen
- State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
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11
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Magierski P, Sekizawa K, Wlazłowski G. Novel Role of Superfluidity in Low-Energy Nuclear Reactions. PHYSICAL REVIEW LETTERS 2017; 119:042501. [PMID: 29341768 DOI: 10.1103/physrevlett.119.042501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Indexed: 06/07/2023]
Abstract
We demonstrate, within symmetry unrestricted time-dependent density functional theory, the existence of new effects in low-energy nuclear reactions which originate from superfluidity. The dynamics of the pairing field induces solitonic excitations in the colliding nuclear systems, leading to qualitative changes in the reaction dynamics. The solitonic excitation prevents collective energy dissipation and effectively suppresses the fusion cross section. We demonstrate how the variations of the total kinetic energy of the fragments can be traced back to the energy stored in the superfluid junction of colliding nuclei. Both contact time and scattering angle in noncentral collisions are significantly affected. The modification of the fusion cross section and possibilities for its experimental detection are discussed.
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Affiliation(s)
- Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Kazuyuki Sekizawa
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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12
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Wlazłowski G, Sekizawa K, Magierski P, Bulgac A, Forbes MM. Vortex Pinning and Dynamics in the Neutron Star Crust. PHYSICAL REVIEW LETTERS 2016; 117:232701. [PMID: 27982659 DOI: 10.1103/physrevlett.117.232701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Indexed: 06/06/2023]
Abstract
The nature of the interaction between superfluid vortices and the neutron star crust, conjectured by Anderson and Itoh in 1975 to be at the heart vortex creep and the cause of glitches, has been a long-standing question in astrophysics. Using a qualitatively new approach, we follow the dynamics as superfluid vortices move in response to the presence of "nuclei" (nuclear defects in the crust). The resulting motion is perpendicular to the force, similar to the motion of a spinning top when pushed. We show that nuclei repel vortices in the neutron star crust, and characterize the force per unit length of the vortex line as a function of the vortex element to the nucleus separation.
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Affiliation(s)
- Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, POLAND
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Kazuyuki Sekizawa
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, POLAND
| | - Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, POLAND
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Aurel Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Michael McNeil Forbes
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 98164-2814, USA
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13
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Bulgac A, Magierski P, Roche KJ, Stetcu I. Induced Fission of (240)Pu within a Real-Time Microscopic Framework. PHYSICAL REVIEW LETTERS 2016; 116:122504. [PMID: 27058076 DOI: 10.1103/physrevlett.116.122504] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Indexed: 06/05/2023]
Abstract
We describe the fissioning dynamics of ^{240}Pu from a configuration in the proximity of the outer fission barrier to full scission and the formation of the fragments within an implementation of density functional theory extended to superfluid systems and real-time dynamics. The fission fragments emerge with properties similar to those determined experimentally, while the fission dynamics appears to be quite complex, with many excited shape and pairing modes. The evolution is found to be much slower than previously expected, and the ultimate role of the collective inertia is found to be negligible in this fully nonadiabatic treatment of nuclear dynamics, where all collective degrees of freedom (CDOF) are included (unlike adiabatic treatments with a small number of CDOF).
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Affiliation(s)
- Aurel Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Piotr Magierski
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
- Faculty of Physics, Warsaw University of Technology, ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - Kenneth J Roche
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Ionel Stetcu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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14
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Francos J, García-Garrido SE, Borge J, Suárez FJ, Cadierno V. Butadiene dyes based on 3-(dicyanomethylidene)indan-1-one and 1,3-bis(dicyanomethylidene)indane: synthesis, characterization and solvatochromic behaviour. RSC Adv 2016. [DOI: 10.1039/c5ra27005g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Novel 1,1-diaryl-substituted butadiene dyes containing 3-(dicyanomethylidene)indan-1-one and 1,3-bis(dicyanomethylidene)indane have been synthetized, and their light absorption and solvatochromic properties evaluated.
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Affiliation(s)
- Javier Francos
- Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC)
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Departamento de Química Orgánica e Inorgánica
- Instituto Universitario de Química Organometálica “Enrique Moles”
- Facultad de Química
| | - Sergio E. García-Garrido
- Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC)
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Departamento de Química Orgánica e Inorgánica
- Instituto Universitario de Química Organometálica “Enrique Moles”
- Facultad de Química
| | - Javier Borge
- Departamento de Química Física y Analítica
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Facultad de Química
- Universidad de Oviedo
- E-33006 Oviedo
| | - Francisco J. Suárez
- Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC)
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Departamento de Química Orgánica e Inorgánica
- Instituto Universitario de Química Organometálica “Enrique Moles”
- Facultad de Química
| | - Victorio Cadierno
- Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC)
- Centro de Innovación en Química Avanzada (ORFEO-CINQA)
- Departamento de Química Orgánica e Inorgánica
- Instituto Universitario de Química Organometálica “Enrique Moles”
- Facultad de Química
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15
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Stetcu I, Bertulani CA, Bulgac A, Magierski P, Roche KJ. Relativistic Coulomb excitation within the time dependent superfluid local density approximation. PHYSICAL REVIEW LETTERS 2015; 114:012701. [PMID: 25615463 DOI: 10.1103/physrevlett.114.012701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 06/04/2023]
Abstract
Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus (238)U. The approach is based on the superfluid local density approximation formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We compute the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance, and giant quadrupole modes are excited during the process. The one-body dissipation of collective dipole modes is shown to lead a damping width Γ(↓)≈0.4 MeV and the number of preequilibrium neutrons emitted has been quantified.
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Affiliation(s)
- I Stetcu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C A Bertulani
- Department of Physics and Astronomy, Texas A & M University-Commerce, Commerce, Texas 75429, USA
| | - A Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - P Magierski
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Faculty of Physics, Warsaw University of Technology, ulica Koszykowa 75, 00-662 Warsaw, Poland
| | - K J Roche
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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Muñoz Mateo A, Brand J. Chladni solitons and the onset of the snaking instability for dark solitons in confined superfluids. PHYSICAL REVIEW LETTERS 2014; 113:255302. [PMID: 25554892 DOI: 10.1103/physrevlett.113.255302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Indexed: 06/04/2023]
Abstract
Complex solitary waves composed of intersecting vortex lines are predicted in a channeled superfluid. Their shapes in a cylindrical trap include a cross, spoke wheels, and Greek Φ, and trace the nodal lines of unstable vibration modes of a planar dark soliton in analogy to Chladni's figures of membrane vibrations. The stationary solitary waves extend a family of solutions that include the previously known solitonic vortex and vortex rings. Their bifurcation points from the dark soliton indicating the onset of new unstable modes of the snaking instability are predicted from scale separation for Bose-Einstein condensates (BECs) and superfluid Fermi gases across the BEC-BCS crossover, and confirmed by full numerical calculations. Chladni solitons could be observed in ultracold gas experiments by seeded decay of dark solitons.
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Affiliation(s)
- A Muñoz Mateo
- Centre for Theoretical Chemistry and Physics and New Zealand Institute for Advanced Study, Massey University, Private Bag 102904 NSMC, Auckland 0745, New Zealand
| | - J Brand
- Centre for Theoretical Chemistry and Physics and New Zealand Institute for Advanced Study, Massey University, Private Bag 102904 NSMC, Auckland 0745, New Zealand
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17
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Bulgac A, Forbes MM, Kelley MM, Roche KJ, Wlazłowski G. Quantized superfluid vortex rings in the unitary Fermi gas. PHYSICAL REVIEW LETTERS 2014; 112:025301. [PMID: 24484022 DOI: 10.1103/physrevlett.112.025301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Indexed: 06/03/2023]
Abstract
In a recent article, Yefsah et al. [Nature (London) 499, 426 (2013)] report the observation of an unusual excitation in an elongated harmonically trapped unitary Fermi gas. After phase imprinting a domain wall, they observe oscillations almost an order of magnitude slower than predicted by any theory of domain walls which they interpret as a "heavy soliton" of inertial mass some 200 times larger than the free fermion mass or 50 times larger than expected for a domain wall. We present compelling evidence that this "soliton" is instead a quantized vortex ring, by showing that the main aspects of the experiment can be naturally explained within the framework of time-dependent superfluid density functional theories.
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Affiliation(s)
- Aurel Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Michael McNeil Forbes
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1550, USA and Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
| | - Michelle M Kelley
- Department of Physics, University of Illinois at Urbana-Champaign, Il 61801-3080, USA
| | - Kenneth J Roche
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - Gabriel Wlazłowski
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662 Warsaw, Poland
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Bulgac A, Forbes MM, Sharma R. Strength of the vortex-pinning interaction from real-time dynamics. PHYSICAL REVIEW LETTERS 2013; 110:241102. [PMID: 25165904 DOI: 10.1103/physrevlett.110.241102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Indexed: 06/03/2023]
Abstract
We present an efficient and general method to compute vortex-pinning interactions--which arise in neutron stars, superconductors, and trapped cold atoms--at arbitrary separations using real-time dynamics. This method overcomes uncertainties associated with matter redistribution by the vortex position and the related choice of ensemble that plague the typical approach of comparing energy differences between stationary pinned and unpinned configurations: uncertainties that prevent agreement in the literature on the sign and magnitude of the vortex-nucleus interaction in the crust of neutron stars. We demonstrate and validate the method with Gross-Pitaevskii-like equations for the unitary Fermi gas, and demonstrate how the technique of adiabatic state preparation with time-dependent simulation can be used to calculate vortex-pinning interactions in fermionic systems such as the vortex-nucleus interaction in the crust of neutron stars.
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Affiliation(s)
- Aurel Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
| | - Michael McNeil Forbes
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA and Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1550, USA
| | - Rishi Sharma
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
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Wei R, Mueller EJ. Pair density waves and vortices in an elongated spin-1/2 Fermi gas. PHYSICAL REVIEW LETTERS 2012; 108:245301. [PMID: 23004285 DOI: 10.1103/physrevlett.108.245301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Indexed: 06/01/2023]
Abstract
We study the vortex structures of a (pseudo)spin-1/2 Fermi gas experiencing a uniform effective magnetic field in an anisotropic trap that interpolates between quasi-one dimensional (1D) and quasi-two dimensional (2D). At a fixed chemical potential, reducing the anisotropy (or equivalently increasing the attractive interactions or increasing the magnetic field) leads to instabilities towards pair density waves and vortex lattices. Reducing the chemical potential stabilizes the system. We calculate the phase diagram and explore the density and pair density. The structures are similar to those predicted for superfluid Bose gases. We further calculate the paired fraction, showing how it depends on the chemical potential and anisotropy.
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Affiliation(s)
- Ran Wei
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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Bulgac A, Luo YL, Roche KJ. Quantum shock waves and domain walls in the real-time dynamics of a superfluid unitary Fermi gas. PHYSICAL REVIEW LETTERS 2012; 108:150401. [PMID: 22587233 DOI: 10.1103/physrevlett.108.150401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/18/2011] [Indexed: 05/31/2023]
Abstract
We show that in the collision of two superfluid fermionic atomic clouds one observes the formation of quantum shock waves as discontinuities in the number density and collective flow velocity. Domain walls, which are topological excitations of the superfluid order parameter, are also generated and exhibit abrupt phase changes by π and slower motion than the shock waves. The domain walls are distinct from the gray soliton train or number density ripples formed in the wake of the shock waves and observed in the collisions of superfluid bosonic atomic clouds. Domain walls with opposite phase jumps appear to collide elastically.
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Affiliation(s)
- Aurel Bulgac
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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Tiribocchi A, Gonnella G, Marenduzzo D, Orlandini E, Salvadore F. Bistable defect structures in blue phase devices. PHYSICAL REVIEW LETTERS 2011; 107:237803. [PMID: 22182126 DOI: 10.1103/physrevlett.107.237803] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Indexed: 05/31/2023]
Abstract
Blue phases are liquid crystals made up by networks of defects, or disclination lines. While existing phase diagrams show a striking variety of competing metastable topologies for these networks, very little is known as to how to kinetically reach a target structure, or how to switch from one to the other, which is of paramount importance for devices. We theoretically identify two confined blue phase I systems in which by applying an appropriate series of electric field it is possible to select one of two bistable defect patterns. Our results may be used to realize new generation and fast switching energy-saving bistable devices in ultrathin surface treated blue phase I wafers.
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Affiliation(s)
- A Tiribocchi
- Dipartimento di Fisica and Sezione INFN di Bari, Università di Bari, 70126 Bari, Italy
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