Critical velocity of superfluid flow through single-barrier and periodic potentials
نویسندگان
چکیده
منابع مشابه
Critical velocity for superfluid flow across the BEC-BCS crossover.
Critical velocities have been observed in an ultracold superfluid Fermi gas throughout the BEC-BCS crossover. A pronounced peak of the critical velocity at unitarity demonstrates that superfluidity is most robust for resonant atomic interactions. Critical velocities were determined from the abrupt onset of dissipation when the velocity of a moving one-dimensional optical lattice was varied. The...
متن کاملCritical Flow of Superfluid Helium-4 through a Submicron Aperture: Width of the Critical Transition
1. EXPERIMENT We-have observed that the critical velocity of the _ flow of superfluid 4He through a submicron aperture exhibits fluctuations which increase with temperature. We have analyzed these fluctuations in order to gain information about the velocity dependence of the probability of occurrence of dissipative phase-slip events. These measurements were made with the same apparatus and duri...
متن کاملCritical superfluid velocity in a trapped dipolar gas.
We investigate the superfluid properties of a dipolar Bose-Einstein condensate (BEC) in a fully three-dimensional trap. Specifically, we estimate a superfluid critical velocity for this system by applying the Landau criterion to its discrete quasiparticle spectrum. We test this critical velocity by direct numerical simulation of condensate depletion as a blue-detuned laser moves through the con...
متن کاملCritical flow and dissipation in a quasi–one-dimensional superfluid
In one of the most celebrated examples of the theory of universal critical phenomena, the phase transition to the superfluid state of (4)He belongs to the same three-dimensional (3D) O(2) universality class as the onset of ferromagnetism in a lattice of classical spins with XY symmetry. Below the transition, the superfluid density ρs and superfluid velocity v s increase as a power law of temper...
متن کاملdiagnostic and developmental potentials of dynamic assessment for writing skill
این پایان نامه بدنبال بررسی کاربرد ارزیابی مستمر در یک محیط یادگیری زبان دوم از طریق طرح چهار سوال تحقیق زیر بود: (1) درک توانایی های فراگیران زمانیکه که از طریق برآورد عملکرد مستقل آنها امکان پذیر نباشد اما در طول جلسات ارزیابی مستمر مشخص شوند; (2) امکان تقویت توانایی های فراگیران از طریق ارزیابی مستمر; (3) سودمندی ارزیابی مستمر در هدایت آموزش فردی به سمتی که به منطقه ی تقریبی رشد افراد حساس ا...
15 صفحه اولذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physical Review A
سال: 2009
ISSN: 1050-2947,1094-1622
DOI: 10.1103/physreva.80.053602