From: Matthew Davis <mdavis_at_physics.uq.edu.au>

Date: Mon, 6 Mar 2006 09:30:10 +1000 (EST)

Date: Mon, 6 Mar 2006 09:30:10 +1000 (EST)

The following message was sent to the matts_arxiv list by Matthew Davis <mdavis_at_physics.uq.edu.au>

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Matt.

-- ------------------------------------------------------------------------- Dr M. J. Davis, Senior Lecturer in Physics School of Physical Sciences, email: mdavis_at_physics.uq.edu.au University of Queensland, ph : +61 7 334 69824 Brisbane, QLD 4072, fax : +61 7 336 51242 Australia. http://www.physics.uq.edu.au/people/mdavis/ ------------------------------------------------------------------------- ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602572 Date: Fri, 24 Feb 2006 01:24:49 GMT (429kb) Title: Dynamical Instability of a Rotating Dipolar Bose-Einstein Condensate Authors: R.M.W. van Bijnen, D.H.J. O'Dell, N.G. Parker and A.M. Martin Comments: 5 pages, including 3 figures Subj-class: Other \\ We calculate the static solutions of a rotating harmonically trapped dilute gas Bose-Einstein condensate in the presence of long range dipolar interactions, based on the hydrodynamic model. In particular we focus on the dynamical instability of our solutions, for weakly anisotropic traps. When the trap anisotropy is introduced adiabatically, at fixed rotation frequency, $\Omega$, the upper bound for the unstable region in $\Omega$ is decreased in the presence of dipolar interactions. By considering dynamical perturbations we also find that for fixed trap anisotropy and adiabatically increasing rotational frequency that the dynamically unstable region in $\Omega$ widens, in a non-trivial manner, as the strength of the dipole interactions is increased. \\ ( http://arXiv.org/abs/cond-mat/0602572 , 429kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602582 Date: Fri, 24 Feb 2006 10:32:14 GMT (338kb) Title: Analysis of an atom laser based on the spatial control of the scattering length Authors: Alicia V. Carpentier, Humberto Michinel, Mar\'{\i}a I. Rodas-Verde, V\'{\i}ctor M. P\'erez-Garc\'{\i}a Comments: Submitted to Phys. Rev. A Subj-class: Other \\ In this paper we analyze atom lasers based on the spatial modulation of the scattering length of a Bose-Einstein Condensate. We demonstrate, through numerical simulations and approximate analytical methods, the controllable emission of matter-wave bursts and study the dependence of the process on the spatial dependence of the scattering length along the axis of emission. We also study the role of an additional modulation of the scattering length in time. \\ ( http://arXiv.org/abs/cond-mat/0602582 , 338kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602525 replaced with revised version Thu, 23 Feb 2006 23:23:24 GMT (429kb) Title: Superfluid phases of the three-species fermion gas Authors: Paulo F. Bedaque, Jos\'e P. D'Incao Comments: 4 pages, 1 figure, typos corrected and references added Subj-class: Other; Atomic Physics \\ ( http://arXiv.org/abs/cond-mat/0602525 , 429kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602568 replaced with revised version Fri, 24 Feb 2006 03:54:50 GMT (291kb) Title: Homogeneous Fermion Superfluid with Unequal Spin Populations Authors: Tin-Lun Ho and Hui Zhai Comments: 4 pages, 3 figures Subj-class: Superconductivity \\ ( http://arXiv.org/abs/cond-mat/0602568 , 291kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0602202 Date: Fri, 24 Feb 2006 09:54:22 GMT (351kb) Title: Non-Gaussian states from continuous-wave Gaussian light sources Authors: Klaus Molmer \\ We present a general analysis of the state obtained by subjecting the output from a continuous-wave (cw) Gaussian field to non-Gaussian measurements. The generic multimode state of cw Gaussian fields is characterized by an infinite dimensional covariance matrix involving the noise correlations of the source. Our theory extracts the information relevant for detection within specific temporal output modes from these correlation functions . The formalism is applied to schemes for production of non-classical light states from a squeezed beam of light. \\ ( http://arXiv.org/abs/quant-ph/0602202 , 351kb) ------------------------------------------------------------------------------ \\ Paper (*cross-listing*): hep-th/0602236 Date: Wed, 22 Feb 2006 20:32:10 GMT (38kb) Title: Nonlocality and quantum-like behavior from classical fields Authors: B. Holdom Comments: 19 pages, 5 figures \\ By averaging over an ensemble of field configurations, a classical field theory can display many of the characteristics of quantum field theory, including Lorentz invariance, a loop expansion, and renormalization effects. There is additional freedom in how the ensemble is chosen. When the field mode amplitudes have a Gaussian distribution, and the mode phases are randomly distributed, we review the known differences between the classical and quantum theories. When the mode amplitudes are fixed, or have a nongaussian distribution, the quartic and higher correlations among the free fields are modified, seemingly in a nonlocal way. We show how this in turn affects the perturbative expansion. We focus on $\lambda\phi^4$ theory in 1+1 dimensions and use lattice simulations to augment our study. We give examples of how these nonlocal correlations induce quantum-like behavior, at both weak and strong coupling. \\ ( http://arXiv.org/abs/hep-th/0602236 , 38kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602614 Date: Mon, 27 Feb 2006 01:34:48 GMT (374kb) Title: Phase Transitions in Ultra-Cold Two-Dimensional Bose Gases Authors: D. A. W. Hutchinson and P. B. Blakie Subj-class: Statistical Mechanics; Superconductivity \\ We briefly review the theory of Bose-Einstein condensation in the two-dimensional trapped Bose gas and, in particular the relationship to the theory of the homogeneous two-dimensional gas and the Berezinskii-Kosterlitz-Thouless phase. We obtain a phase diagram for the trapped two-dimensional gas, finding a critical temperature above which the free energy of a state with a pair of vortices of opposite circulation is lower than that for a vortex-free Bose-Einstein condensed ground state. We identify three distinct phases which are, in order of increasing temperature, a phase coherent Bose-Einstein condensate, a vortex pair plasma with fluctuating condensate phase and a thermal Bose gas. The thermal activation of vortex-antivortex pair formation is confirmed using finite-temperature classical field simulations. \\ ( http://arXiv.org/abs/cond-mat/0602614 , 374kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602616 Date: Mon, 27 Feb 2006 04:07:49 GMT (93kb) Title: Commensurate mixtures of ultra-cold atoms in one dimension Authors: L. Mathey Comments: 4 pages, 2 figures Subj-class: Other \\ We study binary mixtures of ultra-cold atoms, confined to one dimension in an optical lattice, with commensurate densities. Within a Luttinger liquid description, which treats various mixtures on equal footing, we derive a system of renormalization group equations at second order, from which we determine the rich phase diagrams of these mixtures, which include charge/spin density wave order, singlet and triplet pairing, polaron pairing, and a supersolid phase. Various methods to detect our results experimentally are discussed. \\ ( http://arXiv.org/abs/cond-mat/0602616 , 93kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602620 Date: Mon, 27 Feb 2006 10:20:34 GMT (15kb) Title: Composite-fermion description of rotating Bose gases at low angular momenta Authors: Nicolay Korslund and Susanne Viefers Comments: 7 pages (RevTeX), 1 figure. Submitted to Phys Rev A Report-no: OSLO-TP 1-06 Subj-class: Mesoscopic Systems and Quantum Hall Effect \\ We study the composite fermion construction at and below the single vortex ($L=N$) state of weakly interacting rotating Bose gases, presenting a new method for handling the large number of derivatives typically occurring via the Slater determinant. Remarkably, the CF wave function at $L=N$ becomes {\em exact} in the large $N$ limit, even though this construction is not, {\em a priori}, expected to work in the low angular momentum regime. This implies an interesting mathematical identity which may be useful in other contexts. \\ ( http://arXiv.org/abs/cond-mat/0602620 , 15kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602622 Date: Mon, 27 Feb 2006 11:26:52 GMT (67kb) Title: Anderson localization of elementary excitations in a one dimensional Bose-Einstein condensate Authors: Nicolas Bilas and Nicolas Pavloff Comments: 11 pages, 6 figures Subj-class: Other \\ We study the elementary excitations of a transversely confined Bose-Einstein condensate in presence of a weak axial random potential. We determine the localization length (i) at low energy, for a domain of linear densities ranging from the Tonks-Girardeau to the transverse Thomas-Fermi regime, in the case of a white noise potential and (ii) for all the range of energies, in the ``one-dimensional mean field regime'', in the case where the randomness is induced by a series of randomly placed point-like impurities. \\ ( http://arXiv.org/abs/cond-mat/0602622 , 67kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602626 Date: Mon, 27 Feb 2006 13:12:53 GMT (144kb) Title: Bifurcations in Resonance Widths of an Open Bose-Hubbard Dimer Authors: M. Hiller, T. Kottos, A. Ossipov Comments: 4 pages, 3 figures Subj-class: Other \\ We investigate the structure of resonance widths of a Bose-Hubbard Dimer with intersite hopping amplitude $k$, which is coupled to continuum at one of the sites with strength $\gamma$. Using an effective non-Hermitian Hamiltonian formalism, we show that by varying the on-site interaction term $\chi$ the resonances undergo consequent bifurcations. For $\Lambda=k/\gamma\geq 0.5$, the bifurcation points follow a scaling law ${\tilde \chi}_n \equiv \chi_n N/k = f_{\Lambda}(n-0.5/\Lambda)$, where $N$ is the number of bosons. For the function $f_{\Lambda}$ two different $\Lambda$ dependences are found around the minimum and the maximum bifurcation point. \\ ( http://arXiv.org/abs/cond-mat/0602626 , 144kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602630 Date: Mon, 27 Feb 2006 14:11:14 GMT (4kb) Title: Relation between the thermodynamic Casimir effect in Bose-gas slabs and critical Casimir forces Authors: A. Gambassi and S. Dietrich Comments: Comment on cond-mat/0507263 Subj-class: Statistical Mechanics \\ In a recent letter, Martin and Zagrebnov [Europhys. Lett., 73 (2006) 1] discussed the thermodynamic Casimir effect for the ideal Bose gas confined in a thin film. We point out that their findings can be expressed in terms of previous general results for the Casimir effect induced by confined critical fluctuations. This highlights the links between the Casimir effect in the contexts of critical phenomena and Bose-Einstein condensation. \\ ( http://arXiv.org/abs/cond-mat/0602630 , 4kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0510214 replaced with revised version Mon, 27 Feb 2006 17:26:05 GMT (21kb) Title: Worm Algorithm for Continuous-space Path Integral Monte Carlo Simulations Authors: M. Boninsegni, N. Prokof'ev and B. Svistunov Comments: Fig. 2 differs from that of published version (includes data for larger system sizes) Subj-class: Statistical Mechanics Journal-ref: Phys. Rev. Lett. 96, 070601 (2006) \\ ( http://arXiv.org/abs/cond-mat/0510214 , 21kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0601432 replaced with revised version Fri, 24 Feb 2006 23:20:59 GMT (456kb) Title: Atomic matter of non-zero momentum Bose-Einstein condensation and orbital current order Authors: W. Vincent Liu and Congjun Wu Comments: 9 pages, 7 figures (with one in Appendix); Revised the experimental protocol for preparing the model system Subj-class: Other; Strongly Correlated Electrons \\ ( http://arXiv.org/abs/cond-mat/0601432 , 456kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0508172 replaced with revised version Mon, 27 Feb 2006 08:51:20 GMT (668kb) Title: Cold atom dynamics in a quantum optical lattice potential Authors: Christoph Maschler, Helmut Ritsch Comments: 4 pages, 5 figures, corrected typos Journal-ref: Phys. Rev. Lett. 95, 260401 (2005) \\ ( http://arXiv.org/abs/quant-ph/0508172 , 668kb) ------------------------------------------------------------------------------ \\ Paper: physics/0602181 Date: Mon, 27 Feb 2006 14:33:25 GMT (41kb) Title: Control of Ultra-cold Inelastic Collisions by Feshbash Resonances and Quasi-One-Dimensional Confinement Authors: V. A. Yurovsky (1) and Y. B. Band (2) ((1) Tel Aviv University, Israel, (2) Ben-Gurion University, Beer-Sheva, Israel) Comments: 5 pages, 1 figure Subj-class: Atomic Physics \\ Cold inelastic collisions of atoms or molecules are analyzed using very general arguments. In free space, the deactivation rate can be enhanced or suppressed together with the scattering length of the corresponding elastic collision via a Feshbach resonance, and by interference of deactivation of the closed and open channels. In reduced dimensional geometries, the deactivation rate decreases with decreasing collision energy and does not increase with resonant elastic scattering length. This has broad implications; e.g., stabilization of molecules in a strongly confining two-dimensional optical lattice, since collisional decay of the highly vibrationally excited states due to inelastic collisions is suppressed. The relation of our results with those based on the Lieb-Liniger model are addressed. \\ ( http://arXiv.org/abs/physics/0602181 , 41kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0602670 Date: Tue, 28 Feb 2006 15:56:12 GMT (90kb) Title: Beyond Mean-Field Theory for Attractive Bosons under Transverse Harmonic Confinement Authors: Luca Salasnich Comments: To be published in J. Phys. B.: At. Mol. Opt. Phys Subj-class: Statistical Mechanics; Other \\ We study a dilute gas of attractive bosons confined in a harmonic cylinder, i.e. under cylindric confinement due to a transverse harmonic potential. We introduce a many-body wave function which extends the Bethe ansatz proposed by McGuire (J. Math. Phys. {\bf 5}, 622 (1964)) by including a variational transverse Gaussian shape. We investigate the ground state properties of the system comparing them with the ones of the one-dimensional (1D) attractive Bose gas. We find that the gas becomes ultra 1D as a consequence of the attractive interaction: the transverse width of the Bose gas reduces by increasing the number of particles up to a critical width below which there is the collapse of the cloud. In addition, we derive a simple analytical expression for the simmetry-breaking solitonic density profile of the ground-state, which generalize the one deduced by Calogero and Degasperis (Phys. Rev. A {\bf 11}, 265 (1975)). This bright-soliton analytical solution shows near the collapse small deviations with respect to the 3D mean-field numerical solution. Finally, we show that our variational Gauss-McGuire theory is always more accurate than the McGuire theory. In addition, we prove that for small numbers of particles the Gauss-McGuire theory is more reliable than the mean-field theory described by the 3D Gross-Pitaevskii equation. \\ ( http://arXiv.org/abs/cond-mat/0602670 , 90kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0503523 replaced with revised version Tue, 28 Feb 2006 15:34:42 GMT (53kb) Title: Thermally induced rotons in two-dimensional dilute Bose gases Authors: Flavio S. Nogueira and Hagen Kleinert Comments: 21 pages; 2 figures; v4: version accepted for publication in PRB; in this version Section IV is considerably extended Subj-class: Other \\ ( http://arXiv.org/abs/cond-mat/0503523 , 53kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0602230 Date: Tue, 28 Feb 2006 10:35:10 GMT (22kb) Title: Ground state approximation for strongly interacting systems in arbitrary dimension Authors: S. Anders, M. B. Plenio, W. D\"ur, F. Verstraete, and H.-J. Briegel Comments: 4 pages, 4 figures \\ We introduce a variational method for the approximation of ground states of strongly interacting spin systems in arbitrary geometries and spatial dimensions. The approach is based on weighted graph states and superpositions thereof. These states allow for the efficient computation of all local observables (e.g. energy) and include states with diverging correlation length and unbounded multi-particle entanglement. As a demonstration we apply our approach to the Ising model on 1D, 2D and 3D square-lattices. We also present generalizations to higher spins and continuous-variable systems, which allows for the investigation of lattice field theories. \\ ( http://arXiv.org/abs/quant-ph/0602230 , 22kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0602236 Date: Tue, 28 Feb 2006 18:49:49 GMT (14kb) Title: Quantum Revivals in Periodically Driven Systems close to nonlinear resonance Authors: Farhan Saif and Mauro Fortunato Comments: 14 pages, 1 figure Journal-ref: Physical Review A 65, 013401 (2002) \\ We calculate the quantum revival time for a wave-packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement. \\ ( http://arXiv.org/abs/quant-ph/0602236 , 14kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0603004 Date: Tue, 28 Feb 2006 23:33:52 GMT (11kb) Title: Towards measuring Entanglement Entropies in Many Body Systems Authors: Israel Klich, Gil Refael, Alessandro Silva Subj-class: Statistical Mechanics \\ We explore the relation between entanglement entropy of quantum many body systems and the distribution of corresponding, properly selected, observables. Such a relation is necessary to actually measure the entanglement entropy. We show that in general, the Shannon entropy of the probability distribution of certain symmetry observables gives a lower bound to the entropy. In some cases this bound is saturated and directly gives the entropy. We also show other cases in which the probability distribution contains enough information to extract the entropy: we show how this is done in several examples including BEC wave functions, the Dicke model, XY spin chain and chains with strong randomness. \\ ( http://arXiv.org/abs/cond-mat/0603004 , 11kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0603011 Date: Wed, 1 Mar 2006 08:26:39 GMT (89kb) Title: BCS-BEC crossover in an asymmetric two-component Fermi gas Authors: Xia-Ji Liu and Hui Hu Comments: 5 pages + 3 figures Subj-class: Statistical Mechanics; Superconductivity \\ We discuss the superfluid phase transition of a strongly interacting Fermi gas with unequal (asymmetric) chemical potentials in two pairing hyperfine states, and map out its phase diagram near the BCS-BEC crossover. Our approach includes the fluctuation contributions of {}``preformed Cooper pairs'' to the thermodynamic potential at finite temperature. We show that, below a critical difference in chemical potentials between species, a normal gas is unstable towards the formation of either a finite-momentum paired Fulde-Ferrell-Larkin-Ovchinnikov superconducting phase or a uniform superfluid, depending on the asymmetry and interaction strengths. We determine the value of critical chemical potential mismatch, and find good qualitative agreement with a recent measurement by Zwierlein \textit{et al.} {[}Science \textbf{311}, 492 (2006){]}. \\ ( http://arXiv.org/abs/cond-mat/0603011 , 89kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0603015 Date: Wed, 1 Mar 2006 09:47:39 GMT (43kb) Title: Collective modes of a quasi two-dimensional Bose condensate in large gas parameter regime Authors: S.R. Mishra, S. P. Ram, Arup Banerjee Comments: 10 pages, 2 figures Subj-class: Other \\ We have theoretically studied the collective modes of a quasi two-dimensional (Q2D) Bose condensate in the large gas parameter regime by using a formalism which treats the interaction energy beyond the mean-field approximation. In the calculation we use the perturbative expansion for the interaction energy by incorporating the Lee, Huang and Yang (LHY) correction term. The results show that incorporation of this higher order term leads to detectable modifications in the mode frequencies. \\ ( http://arXiv.org/abs/cond-mat/0603015 , 43kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0603016 Date: Wed, 1 Mar 2006 10:15:34 GMT (22kb) Title: Feynman-Kac path integral approach for the energy spectrum of many boson systems Authors: S .Datta Comments: 24 pages, 12 Figures Subj-class: Statistical Mechanics \\ We study the ground and excited states of weakly interacting Bose gases (with positive and negative scattering lengths) in connection with Bose Einstein Condensation.. They behave as new quantum fluids (a gas in the weak limit and a liquid in the dense limit and we study their many body physics in the dilute limit within the realistic potential model (Morse type) by Feynman-Kac path integral technique. Within numerical limitations, this method is exact in principle and turns out to be a better alternative to GP as all the ground and excited state properties can be calculated in a much simpler way. \\ ( http://arXiv.org/abs/cond-mat/0603016 , 22kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0501058 replaced with revised version Wed, 1 Mar 2006 12:31:55 GMT (182kb) Title: First-principles quantum dynamics in interacting Bose gases II: stochastic gauges Authors: P. Deuar and P. D. Drummond Comments: 39 pages, 11 figures, 2 tables. Major revision, especially Section 6 (convergence issues) which is almost all new, and also introduction. Now in J phys A format Subj-class: Other Journal-ref: J. Phys. A: Math. Gen. 39 (2006) 2723-2755 \\ ( http://arXiv.org/abs/cond-mat/0501058 , 182kb) ------------------------------------------------------------------------------ \\ Paper: cond-mat/0603030 Date: Thu, 2 Mar 2006 02:37:11 GMT (19kb) Title: The Mott insulator phase of the one dimensional Bose-Hubbard model Authors: Bogdan Damski and Jakub Zakrzewski Comments: 4 pages, 4 figures, 1 table Report-no: LAUR-06-1357 Subj-class: Other \\ The one dimensional Bose-Hubbard model at a unit filling factor is considered. We do a very high order symbolic perturbative expansion in hopping (tunneling) coupling. Analytical expressions are presented for different ground state quantities: energy per site, variance of on-site occupation, correlation functions: <a_j^\dag a_{j+r}> and <n_j n_{j+r}>. Perturbative predictions are compared to numerical findings and good agreement is found in the Mott insulator phase. These results are of direct relevance to future experiments in ultra cold atomic gases placed in homogeneous lattices. \\ ( http://arXiv.org/abs/cond-mat/0603030 , 19kb) ------------------------------------------------------------------------------ \\ Paper: quant-ph/0603016 Date: Thu, 2 Mar 2006 12:38:36 GMT (255kb) Title: Quantum correlations of two optical fields close to electromagnetically induced transparency Authors: Alice Sinatra (LKB - Lhomond) Comments: 4 pages, 6 figures Proxy: ccsd ccsd-00019947 \\ For two cavity modes exciting a $\Lambda$ transition close to electromagnetically induced transparency we show the existence of a universal dispersive bistability curve dividing the parameter space into two regions in which the system acts either as an ideal "squeezer" or a quantum non demolition device. We use a fully quantum 3-level model including cavity losses and spontaneous emission to calculate mean field intensities and quantum fluctuations as a function of the cavity length that could be directly compared with experiment. Simple analytical predictions are obtained in the good cavity limit in which the atomic variables are adiabatically eliminated. \\ ( http://arXiv.org/abs/quant-ph/0603016 , 255kb) ------------------------------------------------------------------------------Received on Mon Mar 06 2006 - 09:30:10 EST

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