Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0802.3392 · Physical Review A

Single-atom-aided probe of the decoherence of a Bose-Einstein condensate

H. T. Ng, Sougato Bose

Published Aug 6, 2008• 36 citations
arXivHTMLPDF

Abstract

We study a two-level atom coupled to a Bose-Einstein condensate. We show that the rules governing the decoherence of mesoscopic superpositions involving different classical-like states of the condensate can be probed using this system. This scheme is applicable irrespective of whether the condensate is initially in a coherent, thermal, or more generally, in any mixture of coherent states. The effects of atom loss and finite temperature to the decoherence can therefore be studied. We also discuss the various noise sources causing the decoherence.

DOI
10.1103/physreva.78.023610

Related papers

Rydberg impurities control and probe superpositions of Bose-Einstein Condensates

S. Rammohan, Shiva Kant Tiwari, Adya Prasad Mishra +5 more

We show that two major facets of the decoherence paradigm are experimentally accessible for a single impurity atom embedded in a Bose-Einstein condensate, when the impurity is brought into an electronic superposition of two Rydberg states. Not only can the electronic decoherence of the Rydberg atom be read out by microwave interferometry, the platform also provides unique access to the accompanying entangled state of the environment. We theoretically demonstrate signatures of the latter in total atom densities during the transient time in which the impurity is becoming entangled with the medium but the resultant decoherence is not complete yet. The Rydberg impurity thus provides a handle to initiate and read-out mesoscopically entangled superposition states of Bose atom clouds affecting about 500 condensate atoms. We find that the time-scale for its creation and decoherence can be tuned from the order of nanoseconds to microseconds by choice of the excited Rydberg principal quantum number $\nu$, and that Rydberg decoherence dynamics is typically non- Markovian.

•Nov 22, 2020•0 citations

Mesoscopic quantum superpositions in bimodal Bose-Einstein condensates: Decoherence and strategies to counteract it

Krzysztof Pawłowski, Matteo Fadel, Philipp Treutlein +2 more

We study theoretically the interaction-induced generation of mesoscopic coherent spin state superpositions (small-particle-number cat states) from an initial coherent spin state in bimodal Bose-Einstein condensates and the subsequent phase revival, including decoherence due to particle losses and fluctuations of the total particle number. In a full multimode description, we propose a preparation procedure of the initial coherent spin state and we study the effect of preexisting thermal fluctuations on the phase revival, and on the spin and orbito-spinorial cat-state fidelities.

arXiv:1703.07291•Physical Review A•Jun 15, 2017•31 citations

Bose-Einstein condensate in a double-well potential as an open quantum system

Janne Ruostekoski, Daniel F. Walls

We study the dynamics of a Bose-Einstein condensate in a double-well potential in the two-mode approximation. The dissipation of energy from the condensate is described by the coupling to a thermal reservoir of noncondensate modes. As a consequence of the coupling, the self-locked population imbalance in the macroscopic quantum self-trapping decays away. We show that a coherent state predicted by spontaneous symmetry breaking is not robust and decoheres rapidly into a statistical mixture due to the interactions between condensate and noncondensate atoms. However, via stochastic simulations we find that with a sufficiently fast measurement rate of the relative phase between the two wells the matter wave coherence is established even in the presence of the decoherence.

arXiv:cond-mat/9803298•Physical Review A•Jul 1, 1998•143 citations

Decoherence in two Bose-Einstein condensates

Le‐Man Kuang, Zhao-Yang Tong, Zhong-Wen Ouyang +1 more

In this paper, decoherence in a system consisting of two Bose-Einstein condensates is investigated analytically. It is indicated that decoherence can be controlled by manipulating the interaction between the system and environment. The influence of the decoherence on quantum coherent atomic tunneling (AT) between two condensates with arbitrary initial states is studied in detail. Analytical expressions of the population difference (PD) and the AT current between two condensates are found. It is shown that the decoherence leads to the decay of the PD and the suppression of the AT current.

arXiv:cond-mat/0003439•Physical Review A•Dec 14, 1999•65 citations

Solitons explore the quantum classical boundary

Aparna Sreedharan, Sarthak Choudhury, Rick Mukherjee +2 more

It is an open fundamental question how the classical appearance of our environment arises from the underlying quantum many-body theory. We propose that the quantum-classical boundary can be probed in collisions of bright solitons in Bose-Einstein condensates, where thousands of atoms form a large compound object at ultra cold temperatures. We show that these collisions exhibit intricate many-body quantum behavior, invalidating mean field theory. Prior to collision, solitons can loose their well defined quantum phase relation through phase diffusion, essentially caused by atom number fluctuations. This dephasing should typically render the subsequent dynamics more classical. Instead, we find that it opens the door for a tremendous proliferation of mesoscopic entanglement: After collision the two solitons find themselves in a superposition state of various constituent atom numbers, positions and velocities, in which all these quantities are entangled with those of the collision partner. As the solitons appear to traverse the quantum-classical boundary back and forth during their scattering process, they emerge as natural probe of mesoscopic quantum coherence and decoherence phenomena.

•Apr 13, 2019•0 citations

Production of mesoscopic superpositions with ultracold atoms

H. T. Ng

We study mesoscopic superpositions of two component Bose-Einstein condensates. Atomic condensates, with long coherence times, are good systems in which to study such quantum phenomena. We show that the mesoscopic superposition states can be rapidly generated in which the atoms dispersively interact with the photon field in a cavity. We also discuss the production of compass states which are macroscopic quantum superposition states. The physical realization of mesoscopic states is important in studying decoherence and precision measurement.

arXiv:0707.2398•Physical Review A•Mar 14, 2008•5 citations
We study a two-level atom coupled to a Bose-Einstein condensate. We show that the rules governing the decoherence of mesoscopic superpositions involving different classical-like states of the condensate can be probed using this system. This scheme is applicable irrespective of whether the condensate is initially in a coherent, thermal, or more generally, in any mixture of coherent states. The effects of atom loss and finite temperature to the decoherence can therefore be studied. We also discuss the various noise sources causing the decoherence.
We show that two major facets of the decoherence paradigm are experimentally accessible for a single impurity atom embedded in a Bose-Einstein condensate, when the impurity is brought into an electronic superposition of two Rydberg states. Not only can the electronic decoherence of the Rydberg atom be read out by microwave interferometry, the platform also provides unique access to the accompanying entangled state of the environment. We theoretically demonstrate signatures of the latter in total atom densities during the transient time in which the impurity is becoming entangled with the medium but the resultant decoherence is not complete yet. The Rydberg impurity thus provides a handle to initiate and read-out mesoscopically entangled superposition states of Bose atom clouds affecting about 500 condensate atoms. We find that the time-scale for its creation and decoherence can be tuned from the order of nanoseconds to microseconds by choice of the excited Rydberg principal quantum number ν\nuν, and that Rydberg decoherence dynamics is typically non- Markovian.
We study theoretically the interaction-induced generation of mesoscopic coherent spin state superpositions (small-particle-number cat states) from an initial coherent spin state in bimodal Bose-Einstein condensates and the subsequent phase revival, including decoherence due to particle losses and fluctuations of the total particle number. In a full multimode description, we propose a preparation procedure of the initial coherent spin state and we study the effect of preexisting thermal fluctuations on the phase revival, and on the spin and orbito-spinorial cat-state fidelities.
We study the dynamics of a Bose-Einstein condensate in a double-well potential in the two-mode approximation. The dissipation of energy from the condensate is described by the coupling to a thermal reservoir of noncondensate modes. As a consequence of the coupling, the self-locked population imbalance in the macroscopic quantum self-trapping decays away. We show that a coherent state predicted by spontaneous symmetry breaking is not robust and decoheres rapidly into a statistical mixture due to the interactions between condensate and noncondensate atoms. However, via stochastic simulations we find that with a sufficiently fast measurement rate of the relative phase between the two wells the matter wave coherence is established even in the presence of the decoherence.
In this paper, decoherence in a system consisting of two Bose-Einstein condensates is investigated analytically. It is indicated that decoherence can be controlled by manipulating the interaction between the system and environment. The influence of the decoherence on quantum coherent atomic tunneling (AT) between two condensates with arbitrary initial states is studied in detail. Analytical expressions of the population difference (PD) and the AT current between two condensates are found. It is shown that the decoherence leads to the decay of the PD and the suppression of the AT current.
It is an open fundamental question how the classical appearance of our environment arises from the underlying quantum many-body theory. We propose that the quantum-classical boundary can be probed in collisions of bright solitons in Bose-Einstein condensates, where thousands of atoms form a large compound object at ultra cold temperatures. We show that these collisions exhibit intricate many-body quantum behavior, invalidating mean field theory. Prior to collision, solitons can loose their well defined quantum phase relation through phase diffusion, essentially caused by atom number fluctuations. This dephasing should typically render the subsequent dynamics more classical. Instead, we find that it opens the door for a tremendous proliferation of mesoscopic entanglement: After collision the two solitons find themselves in a superposition state of various constituent atom numbers, positions and velocities, in which all these quantities are entangled with those of the collision partner. As the solitons appear to traverse the quantum-classical boundary back and forth during their scattering process, they emerge as natural probe of mesoscopic quantum coherence and decoherence phenomena.
We study mesoscopic superpositions of two component Bose-Einstein condensates. Atomic condensates, with long coherence times, are good systems in which to study such quantum phenomena. We show that the mesoscopic superposition states can be rapidly generated in which the atoms dispersively interact with the photon field in a cavity. We also discuss the production of compass states which are macroscopic quantum superposition states. The physical realization of mesoscopic states is important in studying decoherence and precision measurement.