Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit

Squeezing of quantum fluctuations by means of entanglement is a well recognized goal in the field of quantum information science and precision measurements. In particular, squeezing the fluctuations via entanglement between two-level atoms can improve the precision of sensing, clocks, metrology, and spectroscopy. Here, we demonstrate 3.4 dB of metrologically relevant squeezing and entanglement for ~ 10^5 cold cesium atoms via a quantum nondemolition (QND) measurement on the atom clock levels. We show that there is an optimal degree of decoherence induced by the quantum measurement which maximizes the generated entanglement. A two-color QND scheme used in this paper is shown to have a number of advantages for entanglement generation as compared to a single color QND measurement.Comment: 6 pages+suppl, PNAS forma

Sharp regularity results for many-electron wave functions

We show that electronic wave functions Psi of atoms and molecules have a representation Psi=F*phi, where F is an explicit universal factor, locally Lipschitz, and independent of the eigenvalue and the solution Psi itself, and phi has locally bounded second derivatives. This representation turns out to be optimal as can already be demonstrated with the help of hydrogenic wave functions. The proofs of these results are, in an essential way, based on a new elliptic regularity result which is of independent interest. Some identities that can be interpreted as cusp conditions for second order derivatives of Psi are derived.Comment: 43 page

Work, play and boredom

This special issue focuses on the interconnections between work, play and boredom in contemporary organizations and features contributions by Donncha Kavanagh, Joyce Goggin, Abe Walker, Norman Jackson and Pippa Carter, Niels �kerstr�m Andersen, Hanne Knudsen, Ole Bjerg, Sophie-Th�r�se Krempl and Timon Beyes, Rasmus Johnsen, Jacob J. Peters, and Peter Fleming. The contributions seek to shed light on the way in which play is becoming increasingly incorporated within the world of work and open on to the question of how we might problematize this phenomenon. Boredom emerges as a prominent theme that provides a critical - if ambiguous - counterpoint to the management of fun and frivolity within modern-day corporations. Encompassing both sociological and philosophical reflections, the papers in this special issue add to ongoing debates around the politics of play currently taking place in the field of organization studies. This issue emerged from the ephemera conference on the same theme held at the University of St Andrews in May 2010

Circadian control of white and brown adipose tissues

White and brown adipose tissues are highly dynamic organs anticipating and responding to changes in the environment. The circadian timing system facilitates anticipation, and it is therefore not surprising that circadian disturbances, a prominent feature of modern 24/7 society, increase the risk for (cardio)metabolic diseases. In this mini-review, we will address mechanisms and strategies to mitigate disease risk associated with circadian disturbances. In addition, we discuss the opportunities arising from the knowledge we gained about circadian rhythms in these adipose tissues, including the application of chronotherapy, optimizing endogenous circadian rhythms to allow for more effective intervention, and the identification of novel therapeutic targets.Metabolic health: pathophysiological trajectories and therap

Absence of Self-Averaging and Universal Fluctuations in Random Systems Near Critical Points

The distributions P(X) of singular thermodynamic quantities, on an ensemble of d-dimensional quenched random samples of linear size L near a critical point, are analyzed using the renormalization group. For L much larger than the correlation length ξ, we recover strong self-averaging (SA): P(X) approaches a Gaussian with relative squared width RX~(L/ξ)−d. For L≪ξ we show weak SA (RX decays with a small power of L) or no SA [P(X) approaches a non-Gaussian, with universal L-independent relative cumulants], when the randomness is irrelevant or relevant, respectively

Oxidative Damage to DNA and Lipids as Biomarkers of Exposure to Air Pollution

Ba c k g r o u n d: Air pollution is thought to exert health effects through oxidative stress, which causes damage to DNA and lipids. Obj e c t i v e: We determined whether levels of oxidatively damaged DNA and lipid peroxidation products in cells or bodily fluids from humans are useful biomarkers of biologically effective dose in studies of the health effects of exposure to particulate matter (PM) from combustion processes. Data s o u r c e s: We identified publications that reported estimated associations between environmental exposure to PM and oxidative damage to DNA and lipids in PubMed and EMBASE. We also identified publications from reference lists and articles cited in the Web of Science. Data extraction: For each study, we obtained information on the estimated effect size to calculate the standardized mean difference (unitless) and determined the potential for errors in exposure assessment and analysis of each of the biomarkers, for total and stratified formal meta-analyses. Data synthesis: In the meta-analysis, the standardized mean differences (95 % confidence interval) between exposed and unexposed subjects for oxidized DNA and lipids were 0.53 (0.29–0.76) and 0.73 (0.18–1.28) in blood and 0.52 (0.22–0.82) and 0.49 (0.01–0.97) in urine, respectively. The standardized mean difference for oxidized lipids was 0.64 (0.07–1.21) in the airways. Restricting analyses to studies unlikely to have substantial biomarker or exposure measurement error, studies likely to have biomarker and/or exposure error, or studies likely to have both sources of error resulted in standardized mean differences of 0.55 (0.19–0.90), 0.66 (0.37–0.95), and 0.65 (0.34–0.96), respectively. Co n c l u s i o n s: Exposure to combustion particles is consistenly associated with oxidatively damaged DNA and lipids in humans, suggesting that it is possible to use these measurements as biomarkers of biologically effective dose. Key w o r d s: biomarker, DNA damage, lipid peroxidation products, oxidative stress, particulate matter. Environ Health Perspect 118:1126–1136 (2010). doi:10.1289/ehp.0901725 [Onlin

On the Coexistence of Diagonal and off-Diagonal Long-Range Order, a Monte Carlo Study

The zero temperature properties of interacting 2 dimensional lattice bosons are investigated. We present Monte Carlo data for soft-core bosons that demonstrate the existence of a phase in which crystalline long-range order and off-diagonal long-range order (superfluidity) coexist. We comment on the difference between hard and soft-core bosons and compare our data to mean-field results that predict a larger coexistence region. Furthermore, we determine the critical exponents for the various phase transitions.Comment: 7 pages and 8 figures appended in postscript, KA-TFP-93-0