نتایج جستجو برای: quantum vortices

تعداد نتایج: 303309  

Journal: :Physical review 2022

Inspired by Analogue Gravity, superradiance has been previously investigated in Bose-Einstein condensates (BECs). In this work, we revisit problem introducing dissipation to the system. After establishing possibility of quantum vortices dissipative BECs, analyze propagation elementary excitations, and demonstrate existence superradiant modes, which can be interpreted terms ``antiparticles.'' Ou...

2008
Pouyan Ghaemi Frank Wilczek

Vortices in the simplest superconducting state of graphene contain very low energy excitations, whose existence is connected to an index theorem that applies strictly to an approximate form of the relevant Bogoliubov-deGennes equations. When Zeeman interactions are taken into account, the zero modes required by the index theorem are (slightly) displaced. Thus the vortices acquire internal struc...

1992
Theodore J. Allen

In this Letter the method of Lund is applied to formulate a variational principle for the motion of charged vortices in an effective non-linear Schrödinger field theory describing finite size two-dimensional quantum Hall samples under the influence of an arbitrary perpendicular magnetic field. Freezing out variations in the modulus of the effective field yields a U(1) sigma-model. A duality tra...

Journal: :Physical review letters 1996
van Oudenaarden A Mooij

The quantum transport of vortices in very long and narrow arrays of small Josephson junctions has been studied experimentally. The chemical potential of the system can be changed by an external magnetic field. When the vortex density is commensurate with the one-dimensional junction lattice, the vortex mobility vanishes for a finite window of the magnetic field. The localization of the vortices...

2004
H. Saarikoski A. Harju M. J. Puska R. M. Nieminen

We study electronic structures of two-dimensional quantum dots in high magnetic fields using the density-functional theory (DFT) and the exact diagonalization (ED). With increasing magnetic field, beyond the formation of the totally spin-polarized maximum density droplet (MDD) state, the DFT gives the ground-state total angular momentum as a continuous function with well-defined plateaus. The p...

Journal: :Physical review letters 2007
Suk Bum Chung Hendrik Bluhm Eun-Ah Kim

We consider the stability conditions for half-quantum vortices in a quasi-two-dimensional p{x}+ip{y} superconductor (such as Sr2RuO4 is believed to be). The predicted exotic nature of these excitations has recently attracted much attention, but they have not been observed yet. We emphasize that an isolated half-quantum vortex has a divergent energy cost in the bulk due to its unscreened spin cu...

Journal: :The Review of scientific instruments 2008
T W Heitmann K Yu C Song M P DeFeo B L T Plourde M B S Hesselberth P H Kes

We have developed a picovoltmeter using a Nb dc superconducting quantum interference device for measuring the flux-flow voltage from a small number of vortices moving through a submicron weak-pinning superconducting channel. We have applied this picovoltmeter to measure the vortex response in a single channel arranged in a circle on a Corbino disk geometry. The circular channel allows the vorti...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2008
W F Vinen

This paper provides a brief introduction to quantum turbulence in simple superfluids, in which the required rotational motion in the superfluid component is due entirely to the topological defects that are identified as quantized vortices. Particular emphasis is placed on the basic dynamical behaviour of the quantized vortices and on turbulent decay mechanisms at a very low temperature. There a...

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