Low-dimensional systems provide beautiful examples of many-body quantum physics. For one-dimensional (1D) systems, the Luttinger liquid approach provides insight into universal properties. Much is known of the equilibrium state, both in the weakly and strongly interacting regimes. However, it remains a challenge to probe the dynamics by which this equilibrium state is reached. Here we present a direct experimental study of the coherence dynamics in both isolated and coupled degenerate 1D Bose gases. Dynamic splitting is used to create two 1D systems in a phase coherent state. The time evolution of the coherence is revealed through local phase shifts of the subsequently observed interference patterns. Completely isolated 1D Bose gases are observed to exhibit universal sub-exponential coherence decay, in excellent agreement with recent predictions. For two coupled 1D Bose gases, the coherence factor is observed to approach a non-zero equilibrium value, as predicted by a Bogoliubov approach. This coupled-system decay to finite coherence is the matter wave equivalent of phase-locking two lasers by injection. The non-equilibrium dynamics of superfluids has an important role in a wide range of physical systems, such as superconductors, quantum Hall systems, superfluid helium and spin systems. Our experiments studying coherence dynamics show that 1D Bose gases are ideally suited for investigating this class of phenomena.

Potentials for atoms can be created by external fields acting on properties like magnetic moment, charge, polarizability, or by oscillating fields which couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here we present an experimental investigation of the remarkable properties of potentials derived from radio-frequency (RF) coupling between electronic ground states. The coupling is magnetic and the vector character allows to design state dependent potential landscapes. On atom chips this enables robust coherent atom manipulation on much smaller spatial scales than possible with static fields alone. We find no additional heating or collisional loss up to densities approaching 10 15 atoms / cm 3 compared to static magnetic traps. We demonstrate the creation of Bose-Einstein condensates in RF potentials and investigate the difference in the interference between two independently created and two coherently split condensates in identical traps. All together this makes RF dressing a powerful new tool for micro manipulation of atomic and molecular systems. Dressing of internal states of an atom with an external field is a well known technique in quantum optics [1]. The coupling of atomic states to an oscillating field leads to new eigenstates and eigenenergies in the combined system. These dressed states can form adiabatic potentials, which can be employed for atom trapping and manipulation. The most prominent example is the optical dipole potential [2] created when intense coherent light couples ground and electronically excited states of an atom. To create conservative potentials for coherent manipulation spontaneous relaxation of the excited state has to be avoided and hence the light field has to be far detuned. Consequently the magnitude and shape of the dipole potential is given by the local intensity of the light field. Such far detuned dipole potentials are widely used in ultra cold atom experiments [3].Dressing can also be achieved by coupling hyperfine components of the electronic ground state by a magnetic radio-frequency (RF) or micro-wave (MW) field. Dressed state potentials resulting from RF coupling of two spin states in a magnetic field have been studied in neutron optics [4]. Adiabatic potentials induced by coupling hyperfine states with a micro wave have been proposed in Ref. [5], and a detuned micro-wave has been used for trapping ultra cold Cs atoms [6]. The trapping of neutral atoms with RF induced potentials was proposed in [7] and first demonstrated for thermal Rb atoms [8]. Recently RF dressed state potentials were employed for coherent splitting of a one-dimensional Bose-Einstein condensate and matter-wave interference [9]. In this paper, we give for the first time a full experimental demonstra- * Electronic address: hofferberth@atomchip.org tion and analysis of the remarkable properties of these adiabatic RF dressed state potentials, which make them a versatile ...

International audienceFew studies have investigated the independent effects of domain-specific physical activity on mortality. We sought to investigate the association of physical activity performed in different domains of daily living on all-cause, cardiovascular (CVD) and cancer mortality. Using a prospective cohort design, 4,672 men and women, aged 25-74 years, who participated in the baseline examination of the MONICA/KORA Augsburg Survey 1989/1990 were classified according to their activity level (no, light, moderate, vigorous). Domains of self-reported physical activity (work, transportation, household, leisure time) and total activity were assessed by the validated MOSPA (MONICA Optional Study on Physical Activity) questionnaire. After a median follow-up of 17.8 years, a total of 995 deaths occurred, with 452 from CVD and 326 from cancer. For all-cause mortality, hazard ratios and 95% confidence interval (HR, 95% CI) of the highly active versus the inactive reference group were 0.69 (0.48-1.00) for work, 0.48 (0.36-0.65) for leisure time, and 0.73 (0.59-0.90) for total activity after multivariable adjustments. Reduced risks of CVD mortality were observed for high levels of work (0.54, 0.31-0.93), household (0.80, 0.54-1.19), leisure time (0.50, 0.31-0.79) and total activity (0.75, 0.55-1.03). Leisure time (0.36, 0.23-0.59) and total activity (0.62, 0.43-0.88) were associated with reduced risks of cancer mortality. Light household activity was related to lower all-cause (0.82, 0.71-0.95) and CVD (0.72, 0.58-0.89) mortality. No clear effects were found for transportation activities. Our findings suggest that work, household, leisure time and total physical activity, but not transportation activity, may protect from premature mortality

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We study dressed Bose-Einstein condensates in an atom chip radio-frequency trap. We show that in this system sufficiently strong dressing can be achieved to cause the widely used rotating-wave approximation ͑RWA͒ to break down. We present a full calculation of the atom-field coupling which shows that the non-RWA contributions quantitatively alter the shape of the emerging dressed adiabatic potentials. The non-RWA contributions furthermore lead to additional allowed transitions between dressed levels. We use rf spectroscopy of Bose-Einstein condensates trapped in the dressed state potentials to directly observe the transition from the RWA to the beyond-RWA regime.