ELFT HÍRADÓ

[Andras Palyi <palyi AT mail.bme.hu>]

Dear Colleagues, 

The Exotic Quantum Phases seminar series at BME continues next Monday with 
this talk:


Marine Pigneur (TU Wien)
“Relaxation in tunnel coupled 1D superfluids"

Time: 14:15 on Monday (April 15, 2019)
Location: library of the theory department (BME Department of Theoretical 
Physics, Budafoki ut 8., building F, stairway III.)

Abstract: 
"Atomic interactions introduce an intrinsic non-linearity in Bosonic 
Josephson Junctions, making them richer than their condensed matter analogue. 
We experimentally study the effects of particle interactions on the tunneling 
dynamics of two coupled elongated Bose-Einstein condensate. The trapping 
geometry is a tunable double-well generated by an atom chip. 

Using radio-frequency dressing, we deform a single harmonic atom trap, in 
which the atoms are initially condensed, into a double-well potential and 
realize a splitting of the BEC wave function. A large spatial separation and 
a tilt of the double-well enable us to prepare a broad variety of initial 
states by precisely adjusting the initial population and relative phase of 
the two wave packets, while preserving the phase coherence.

In particular, imprinting a global relative phase between the superfluids 
leads to Josephson oscillations that we can investigate for various coupling 
strengths. The observed dynamics exhibits a rapid relaxation toward a 
phase-locked equilibrium state, which goes beyond the predictions of the two 
site Bose-Hubbard model. As the relaxation escapes the existing description, 
both 1D and 3D, we account for it using an empirical friction and investigate 
the dependence of the damping magnitude with our experimental parameters. It 
results that the relaxation does not depend on the tunnel coupling and 
depends on the atom number as N-1/2. We currently search for a relaxation 
mechanism compatible with our experimental observations.”


Best regards,
Andras Palyi