Stability and Density fluctuation of superfluids and supersolids in non-uniform Bose-Einstein condensates

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540361
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: The University of Tokyo
• Principal Investigator: KATO Yusuke 東京大学, 総合文化研究科, 准教授 (20261547)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 超流動 / 量子渦 / 臨界速度 / 密度揺らぎ / エネルギーランドスケープ

Outline of Final Research Achievements

Superfluidity is a macroscopic flow without viscosity and energy dissipation. Superfluid state is stable when the velocity of flow is sufficiently slow. When the velocity exceeds a threshold(which is called critical velocity), the superfluid breaks down accompanied by vortex generation. Physicists try to understand the mechanism of breakdown of superfluidity by making a "map" that tells us how the stable(metastable) and unstable states are connected in the physical space. "The height" in this map corresponds to the energy of each physical state and the map for physicists is called "energy landscape". We have found that the map has more rich structures or connectivity of "valleys" (stable state) and "ridges" than anticipated. Each ridge corresponds to physical state with many pairs of quantum vortices.

Free Research Field

物性理論