Article
Physics, Multidisciplinary
G. Dagvadorj, P. Comaron, M. H. Szyma
Summary: We investigate a four-component polariton system in the optical parametric oscillator regime and find that all four components exhibit the same BKT critical point and algebraic decay of spatial coherence. However, the creation of topological defects near the phase transition is largely independent of intercomponent mode locking and strongly depends on the density within a given mode. This unique characteristic allows us to discover a novel state of matter characterized by the proliferation of topological defects on a superfluid with algebraic decay of coherence, which can be observed in current experiments.
PHYSICAL REVIEW LETTERS
(2023)
Letter
Chemistry, Multidisciplinary
Arthur Veyrat, Valentin Labracherie, Dima L. Bashlakov, Federico Caglieris, Jorge I. Facio, Grigory Shipunov, Titouan Charvin, Rohith Acharya, Yurii Naidyuk, Romain Giraud, Jeroen van den Brink, Bernd Buechner, Christian Hess, Saicharan Aswartham, Joseph Dufouleur
Summary: In this study, it is predicted that broken inversion symmetry and strong spin-orbit coupling in trigonal PtBi2 lead to a type-I Weyl semimetal band structure. Transport measurements reveal unusually robust low dimensional superconductivity in thin exfoliated flakes of PtBi2, with thickness up to 126 nm and critical temperature (T-c) ranging from 275-400 mK. A Berezinskii-Kosterlitz-Thouless transition with critical temperature (T-BKT) around 310 mK is observed in up to 60 nm thick flakes, which is significantly thicker than rare examples of two-dimensional superconductors exhibiting such a transition. PtBi2 thus provides an ideal platform to study low dimensional and unconventional superconductivity in topological semimetals.
Article
Physics, Multidisciplinary
D. Opherden, M. S. J. Tepaske, F. Baertl, M. Weber, M. M. Turnbull, T. Lancaster, S. J. Blundell, M. Baenitz, J. Wosnitza, C. P. Landee, R. Moessner, D. J. Luitz, H. Kuehne
Summary: We report the manifestation of field-induced Berezinskii-Kosterlitz-Thouless (BKT) correlations in the weakly coupled spin-1/2 Heisenberg layers of the molecular-based bulk material. The application of laboratory magnetic fields induces a substantial XY anisotropy of the spin correlations, providing a significant BKT regime. We use nuclear magnetic resonance measurements and quantum Monte Carlo simulations to probe and study the spin correlations.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Zhiyao Zuo, Shuai Yin, Xuanmin Cao, Fan Zhong
Summary: In this study, a series of scaling theories for Kosterlitz-Thouless phase transitions are proposed and verified using a one-dimensional Bose-Hubbard model, improving upon commonly used scaling assumptions and presenting finite-size and finite-entanglement scaling forms. The results show that the rate exponent varies with the distance from the critical point and driving rate, consistent with experimental findings, and that the finite-size and finite-entanglement scaling can well describe the experimental results.
Article
Chemistry, Physical
Wen-He Jiao, Xiao-Feng Xu, Hao Jiang, Zhu-An Xu, Qing-Hu Chen, Guang-Han Cao
Summary: The study demonstrates the presence of BKT transition and Nelson-Kosterlitz jump in high-quality Ba(Fe0.914Co0.086)(2)As-2 single crystals, along with a non-Hall transverse signal exactly at the superconducting transition, which is likely attributed to the guided motion of unbound vortices.
Article
Materials Science, Multidisciplinary
Fernando Gomez-Ortiz, Pablo Garcia-Fernandez, Juan M. Lopez, Javier Junquera
Summary: We investigated the emergence of Berezinskii-Kosterlitz-Thouless (BKT) phases in (PbTiO3)3/(SrTiO3)3 superlattices using second-principles simulations. Under a tensile epitaxial strain of e = 0.25-1%, the local dipole moments within the superlattices are confined to the film-plane, leading to two-dimensional polarization. Our analysis of dipole-dipole correlation decay, density of defects, and temperature dependence supports the existence of a BKT phase, characterized by quasi-long-range order and the presence of tightly bound vortex-antivortex pairs. This proposed superlattice model can be experimentally verified due to its feasibility in fabrication and the imposed mechanical boundary conditions.
Article
Materials Science, Multidisciplinary
Y-H Tseng, F-J Jiang
Summary: By using a supervised neural network trained on a one-dimensional lattice, the study successfully calculated the Berezinskii-Kosterlitz-Thouless phase transitions of two-dimensional classical XY models. The neural network approach proved to be accurate in predicting critical points with minimal information and demonstrated efficiency in computation. This universal neural network is not only valid for symmetry breaking related phase transitions, but also for calculating critical points associated with topology.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
E. S. Klyushina, J. Reuther, L. Weber, A. T. M. N. Islam, J. S. Lord, B. Klemke, M. Mansson, S. Wessel, B. Lake
Summary: The study revealed that BaNi2V2O8 behaves as a two-dimensional antiferromagnet across the entire temperature range, with different behavior patterns emerging as the temperature increases. Close to the ordering temperature TN, the system behaves as a 2D XY antiferromagnet, while above TN, evidence of Berezinskii-Kosterlitz-Thouless behavior driven by vortex excitations was observed.
Article
Optics
Koichiro Furutani, Andrea Perali, Luca Salasnich
Summary: We theoretically investigate the Berezinskii-Kosterlitz-Thouless transition in a binary mixture of bosonic atoms with Rabi coupling. The transition temperature shows a nonmonotonic behavior with respect to the intercomponent coupling and an amplification for finite Rabi coupling. By developing the Nelson-Kosterlitz renormalization-group equations, we clarify the dependence of the transition temperature on the Rabi coupling and the intercomponent coupling. Our results contribute to the understanding of multicomponent quantum systems, such as multiband superconductors.
Article
Optics
Elahe Samimi, Mohammad Hossein Zarei, Afshin Montakhab
Summary: This paper investigates the global entanglement (GE) and conditional global entanglement (Q) in Kosterlitz-Thouless (KT) phase transitions. It finds that while GE does not indicate clear transition points, Q shows strong signatures of the KT transition points. The study also demonstrates that Q can characterize various phases of the model and behaves differently in each phase.
Article
Multidisciplinary Sciences
Krzysztof Gawryluk, Miroslaw Brewczyk
Summary: In this study, the sound propagation in a two-dimensional weakly interacting uniform Bose gas is theoretically explored using classical fields approximation. Density waves generated in both weak and strong perturbation regimes are analyzed, with strong disturbances resulting in a qualitatively different response, identified as quasisolitons. In the strong perturbation regime, quasisolitons break into vortex pairs over time, eventually reaching an equilibrium state characterized by fluctuating in time averaged number of pairs of opposite charge vortices and quasi-long-range order, known as the Berezinskii-Kosterlitz-Thouless (BKT) phase.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Guido Giachetti, Nicolo Defenu, Stefano Ruffo, Andrea Trombettoni
Summary: The article discusses the effect of long-range decaying couplings on the BKT transition, revealing a phase diagram far richer than the short-range scenario, with a quasiordered phase existing between a symmetry broken phase and a disordered phase.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Sujit Sarkar
Summary: The BKT mechanism applies not only to conventional many-body systems, but also to strongly correlated PT symmetry quantum criticality. We observe the presence of hidden QBKT and conventional QBKT for the real part of the potential, with no evidence for the imaginary part. Additionally, we provide exact solutions for the RG flow lines.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Fluids & Plasmas
Kwai-Kong Ng, Ching-Yu Huang, Feng-Li Lin
Summary: The Berezinskii-Kosterlitz-Thouless (BKT) phase transitions of the two-dimensional q-state clock model with q=4 is studied using the neural network (NN) flow method. The Jensen-Shannon divergence (JSD) is adopted as the information-distance measure thermometer to gauge the difference among Monte Carlo configurations at different temperatures, and to identify the critical temperatures of BKT phase transitions. The results show that the NN flow can flow an arbitrary spin state to a fixed-point ensemble of states, and the JSD of the fixed-point ensemble exhibits unique features.
Article
Materials Science, Multidisciplinary
Domenico Giuliano, Phong H. Nguyen, Andrea Nava, Massimo Boninsegni
Summary: We present a theoretical study on the Berezinskii-Kosterlitz-Thouless transition in a two-dimensional superfluid with an externally imposed density modulation. Using analytical and numerical techniques, we show that as the modulation amplitude increases, the system exhibits behavior similar to the anisotropic x-y model, with a lower superfluid transition temperature and anisotropic response, but no dimensional crossover.
