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:cond-mat/0312227

Comment on "Observation of Bose-Einstein Condensation of Molecules", cond-mat/0311617

Michiel Wouters, Jacques Tempere, J. T. Devreese

Published Dec 9, 2003• 0 citations
arXivHTMLPDF

Abstract

In this comment, we argue that the recent experiment of Ketterle and co-workers does not necessarily need to be interpreted as indicating that the true scattering amplitude between two molecules becomes small (8 nm measured vs. 120 nm predicted). Rather it can be interpreted as indicating that the energy of the achieved state is much lower than both the (variational) energy for a BCS state and the energy of a molecular condensate. In this sense, we suggest that the experiment may point to a novel many-body state, that is neither the BCS nor the molecular BEC state, and that still has to be identified.

DOI
10.48550/arxiv.cond-mat/0312227

Related papers

Comment on ``Ramsey Fringes in a Bose-Einstein Condensate between Atoms and Molecules''

Eric Braaten, H.‐W. Hammer, Masaoki Kusunoki

In Phys. Rev. Lett. 89, 180401 (2002) [cond-mat/0204504], Kokkelmans and Holland interpret the results of a recent experiment at JILA that demonstrated atom-molecule coherence in a Bose-Einstein condensate. Using a mean-field approximation to a resonance field theory involving an atom condensate and a molecular condensate, they find that the molecular condensate is tiny compared to the atom condensate. We show that if the probability for the molecular field to create a diatomic molecule is correctly included, the numbers of atoms in the atom condensate and in the condensate of diatomic molecules are comparable.

arXiv:cond-mat/0301489•Jan 24, 2003•1 citation

Long-Range Nature of Feshbach Molecules in Bose-Einstein Condensates

Thorsten Köhler, Thomas Gasenzer, Paul S. Julienne +1 more

We discuss the long-range nature of the molecules produced in recent experiments on molecular Bose-Einstein condensation. The properties of these molecules depend on the full two-body Hamiltonian and not just on the states of the system in the absence of interchannel couplings. The very long-range nature of the state is crucial to the efficiency of production in the experiments. Our many-body treatment of the gas accounts for the full binary physics and describes properly how these molecular condensates can be directly probed.

arXiv:cond-mat/0302082•Physical Review Letters•Dec 2, 2003•49 citations

A new perturbation theory for the superfluid Fermi gas in the molecular Bose-Einstein condensed state

Shina Tan

We demonstrate how solutions to quantum few-fermion scattering problems can be the point-of-departure of a new treatment of a generalized many-body wave function. Our focus is on a particular ansatz for the ground state wave function of a superfluid Fermi gas introduced earlier (cond-mat/0506293). Our method is perturbative in the sense that the probability amplitudes for few-fermion scattering processes are treated as small quantities; it is also NONPERTURBATIVE in the sense that whenever such scattering events occur, nonperturbative quantum few-fermion scattering physics dominates. This approach can be viewed as a new diagrammatic methodology, based on a wave function as distinct from a perturbation series in the interparticle interactions. Some generic properties of the wave function are studied, and its parameters in the Bose-Einstein condensed limit are computed beyond mean-field. These results enable us to predict many observable properties of this Fermi gas with well-controlled accuracy, such as the superfluid pairing function, the four-fermion and six-fermion correlation functions, the momentum distribution, and the two-body reduced density matrix, etc.

arXiv:cond-mat/0510055•Oct 3, 2005•0 citations

Comment on "Stimulated Raman adiabatic passage from an atomic to a molecular Bose-Einstein condensate" (2 pages)

Matt Mackie, Anssi Collin, Juha Javanainen

Physical Review A•Jan 1, 2005•0 citations

Ramsey interferometry with atoms and molecules: Two-body versus many-body phenomena

Krzysztof Góral, Thorsten Köhler, Keith R. Burnett

We discuss the frequency and visibility of atom-molecule Ramsey fringes observed in recent experiments by Claussen et al. [Phys. Rev. A 67, 060701 (2003)]. In these experiments a $^{85}\mathrm{Rb}$ Bose-Einstein condensate was exposed to a sequence of magnetic field pulses on the high-field side of the $155\phantom{\rule{0.3em}{0ex}}\mathrm{G}$ Feshbach resonance. The observed oscillation frequencies largely agree with the theoretically predicted magnetic field dependence of the binding energy of the highest excited diatomic vibrational state, except for a small region very close to the singularity of the scattering length. Our analytic treatment of the experiment, as well as our dynamical simulations, follow the magnitude of the measured oscillation frequencies as well as the visibilities of the Ramsey fringes. We show that significant deviations from a purely binary dynamics, with an associated binding frequency, occur when the spatial extent of the molecular wave function becomes comparable with the mean distance between the atoms in the dilute gas. The experiments thus clearly identify the conditions under which diatomic molecules may be identified as a separate entity of the gas or, conversely, when the concept of binary physics in a many-body environment is bound to break down.

arXiv:cond-mat/0407627•Physical Review A•Feb 9, 2005•15 citations

Observation of Bose-Einstein condensation of molecules

Claudiu Andrei Stan, Martin W. Zwierlein, Christian H. Schunck +2 more

We have observed Bose-Einstein condensation of molecules, created from a spin mixture of fermionic 6Li atoms. The condensate realizes the limit of tightly bound fermion pairs in the crossover between BCS and BEC superfluidity.

Conference on Lasers and Electro-Optics•Jan 1, 2004•22 citations
In this comment, we argue that the recent experiment of Ketterle and co-workers does not necessarily need to be interpreted as indicating that the true scattering amplitude between two molecules becomes small (8 nm measured vs. 120 nm predicted). Rather it can be interpreted as indicating that the energy of the achieved state is much lower than both the (variational) energy for a BCS state and the energy of a molecular condensate. In this sense, we suggest that the experiment may point to a novel many-body state, that is neither the BCS nor the molecular BEC state, and that still has to be identified.
In Phys. Rev. Lett. 89, 180401 (2002) [cond-mat/0204504], Kokkelmans and Holland interpret the results of a recent experiment at JILA that demonstrated atom-molecule coherence in a Bose-Einstein condensate. Using a mean-field approximation to a resonance field theory involving an atom condensate and a molecular condensate, they find that the molecular condensate is tiny compared to the atom condensate. We show that if the probability for the molecular field to create a diatomic molecule is correctly included, the numbers of atoms in the atom condensate and in the condensate of diatomic molecules are comparable.
We discuss the long-range nature of the molecules produced in recent experiments on molecular Bose-Einstein condensation. The properties of these molecules depend on the full two-body Hamiltonian and not just on the states of the system in the absence of interchannel couplings. The very long-range nature of the state is crucial to the efficiency of production in the experiments. Our many-body treatment of the gas accounts for the full binary physics and describes properly how these molecular condensates can be directly probed.
We demonstrate how solutions to quantum few-fermion scattering problems can be the point-of-departure of a new treatment of a generalized many-body wave function. Our focus is on a particular ansatz for the ground state wave function of a superfluid Fermi gas introduced earlier (cond-mat/0506293). Our method is perturbative in the sense that the probability amplitudes for few-fermion scattering processes are treated as small quantities; it is also NONPERTURBATIVE in the sense that whenever such scattering events occur, nonperturbative quantum few-fermion scattering physics dominates. This approach can be viewed as a new diagrammatic methodology, based on a wave function as distinct from a perturbation series in the interparticle interactions. Some generic properties of the wave function are studied, and its parameters in the Bose-Einstein condensed limit are computed beyond mean-field. These results enable us to predict many observable properties of this Fermi gas with well-controlled accuracy, such as the superfluid pairing function, the four-fermion and six-fermion correlation functions, the momentum distribution, and the two-body reduced density matrix, etc.
We discuss the frequency and visibility of atom-molecule Ramsey fringes observed in recent experiments by Claussen et al. [Phys. Rev. A 67, 060701 (2003)]. In these experiments a 85Rb^{85}\mathrm{Rb}85Rb Bose-Einstein condensate was exposed to a sequence of magnetic field pulses on the high-field side of the 155G155\phantom{\rule{0.3em}{0ex}}\mathrm{G}155G Feshbach resonance. The observed oscillation frequencies largely agree with the theoretically predicted magnetic field dependence of the binding energy of the highest excited diatomic vibrational state, except for a small region very close to the singularity of the scattering length. Our analytic treatment of the experiment, as well as our dynamical simulations, follow the magnitude of the measured oscillation frequencies as well as the visibilities of the Ramsey fringes. We show that significant deviations from a purely binary dynamics, with an associated binding frequency, occur when the spatial extent of the molecular wave function becomes comparable with the mean distance between the atoms in the dilute gas. The experiments thus clearly identify the conditions under which diatomic molecules may be identified as a separate entity of the gas or, conversely, when the concept of binary physics in a many-body environment is bound to break down.