Globally symmetric spinor condensates in free space are argued not to support stable topological defects in either two or three dimensions. In the latter case, however, we show that a topological Skyrmion can be stabilized by forcing it to adopt certain density profiles. A sufficient condition for the existence of Skyrmion solutions in three dimensions is formulated and illustrated in simple examples. Our results pertain to Bose-Einstein condensation in 87Rb.
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http://dx.doi.org/10.1103/PhysRevLett.97.080403 | DOI Listing |
Proc Natl Acad Sci U S A
December 2024
School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
Quasiparticles are low-energy excitations with important roles in condensed matter physics. An intriguing example is provided by Majorana quasiparticles, which are equivalent to their antiparticles. Despite being implicated in neutrino oscillations and topological superconductivity, their experimental realizations remain very rare.
View Article and Find Full Text PDFSpinor Bose-Einstein condensate is an ideal candidate for implementing the many-body entanglement, quantum measurement and quantum information processing owing to its inherent spin-mixing dynamics. Here we present a system of an Rb atomic spin-1 Bose-Einstein condensate coupled to an optical ring cavity, in which cavity-mediated nonlinear interactions give rise to saddle points in the semiclassical phase space, providing a general mechanism for exponential fast scrambling and metrological gain augment. We theoretically study metrological gain and fidelity out-of-time-ordered correlator based on time-reversal protocols and demonstrate that exponential rapid scrambling dynamics can enhance quantum metrology.
View Article and Find Full Text PDFWe have theoretically realized a photonic time crystal in a homogeneous spinor exciton-polariton condensate subject to a cavity strain induced energy splitting between the x- and y-polarized polaritons with distinct loss rates. Numerical modeling based on the time-dependent open dissipative Gross-Pitaevskii equation results in the phase transition from linearly-polarized spinor condensate at low pump powers into a circularly-polarized one and then a photonic time crystal at higher pump powers. This phenomenon occurs only under the condition that the lower-energy x-polarized condensate has a higher loss rate than the y-polaried condensate, which can exist intrinsically in the semiconductor microcavities.
View Article and Find Full Text PDFPhys Rev E
April 2024
Laboratory of Mathematics and Complex Systems (Ministry of Education), School of Mathematical Sciences, Beijing Normal University, Beijing 100875, China.
Under investigation are the three-component Gross-Pitaevskii equations in F=1 spinor Bose-Einstein condensates. Various localized waves' generation mechanisms have been derived from plane wave solutions using modulation instability. The perturbed continuous waves produce a large number of rogue wave structures through the split-step Fourier numerical method.
View Article and Find Full Text PDFNat Commun
March 2024
Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
This paper presents our findings on the recursive band gap engineering of chiral fermions in bilayer graphene doubly aligned with hBN. Using two interfering moiré potentials, we generate a supermoiré pattern that renormalizes the electronic bands of the pristine bilayer graphene, resulting in higher order fractal gaps even at very low energies. These Bragg gaps can be mapped using a unique linear combination of periodic areas within the system.
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