Non-linear mixing of Bogoliubov modes in a bosonic Josephson junction
| Autor: | S. Martínez-Garaot, Michele Modugno, Giulio Pettini |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
Josephson effect Condensed Matter::Quantum Gases Quantum Physics education.field_of_study Population FOS: Physical sciences Plasma oscillation 01 natural sciences 010305 fluids & plasmas High Energy Physics - Phenomenology Nonlinear system High Energy Physics - Phenomenology (hep-ph) Quantum Gases (cond-mat.quant-gas) Quantum electrodynamics Excited state 0103 physical sciences Quasiparticle Condensed Matter - Quantum Gases 010306 general physics education Ground state Quantum Physics (quant-ph) Mixing (physics) |
| DOI: | 10.48550/arxiv.1807.06682 |
| Popis: | We revisit the dynamics of a Bose-Einstein condensate in a double-well potential, from the regime of Josephson plasma oscillations to the self-trapping regime, by means of the Bogoliubov quasiparticle projection method. For very small imbalance between left and right wells only the lowest Bogoliubov mode is significantly occupied. In this regime the system performs plasma oscillations at the corresponding frequency, and the evolution of the condensate is characterized by a periodic transfer of population between the ground and the first excited state. As the initial imbalance is increased, more excited modes -- though initially not macroscopically occupied -- get coupled during the evolution of the system. Since their population also varies with time, the frequency spectrum of the imbalance turns out to be still peaked around a single frequency, which is continuously shifted towards lower values. The nonlinear mixing between Bogoliubov modes eventually drives the system into the the self-trapping regime, when the population of the ground state can be transferred completely to the excited states at some time during the evolution. For simplicity, here we consider a one-dimensional setup, but the results are expected to hold also in higher dimensions. Comment: 7 pages, 5 figures |
| Databáze: | OpenAIRE |
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