Physical Review Letters (PHYS REV LETT)

Publications in this journal

• Article: Onthological models predictively inequivalent to quantum theory GianCarlo Ghirardi, Raffaele Romano

  GianCarlo Ghirardi, Raffaele Romano
  [show abstract] [hide abstract]
  ABSTRACT: Recently, it has been argued that no extension of quantum theory can have improved predictive power, under a strong assumption of free choice of the experimental settings, and validity of quantum mechanics. Here, under a different free choice assumption, we describe a model which violates this statement for almost all states of a bipartite two-level system, in a possibly experimentally testable way. From consistency with quantum mechanics and the non-signalling principle, we derive a bound on the local averages for the family of deterministic ontological theories our model belongs to.
  Physical Review Letters 06/2013; 110:170404.
• Article: Broken Symmetries, Zero-Energy Modes, and Quantum Transport in Disordered Graphene: From Supermetallic to Insulating Regimes

  Alessandro Cresti, Frank Ortmann, Thibaud Louvet, Dinh Van Tuan, Stephan Roche
  [show abstract] [hide abstract]
  ABSTRACT: The role of defect-induced zero-energy modes on charge transport in graphene is investigated using Kubo and Landauer transport calculations. By tuning the density of random distributions of monovacancies either equally populating the two sublattices or exclusively located on a single sublattice, all conduction regimes are covered from direct tunneling through evanescent modes to mesoscopic transport in bulk disordered graphene. Depending on the transport measurement geometry, defect density, and broken sublattice-symmetry, the Dirac point conductivity is either exceptionally robust against disorder (supermetallic state) or suppressed through a gap opening or by algebraic localization of zero-energy modes, whereas weak localization and the Anderson insulating regime are obtained for higher energies. These findings clarify the contribution of zero-energy modes to transport at the Dirac point, hitherto controversial.
  Physical Review Letters 04/2013; 110(19):196601.
• Article: Compositional Thresholds and Anomalies in Connection with Stiffness Transitions in Network Glasses

  M. Bauchy, M. Micoulaut, M. Boero, C.Massobrio
  [show abstract] [hide abstract]
  ABSTRACT: The structural and dynamical properties of amorphous and liquid AsxSe1-x (0.2<x<0.4) are studied by first principles molecular dynamics. Within the above range of compositions, thresholds and anomalies are found in the behavior of reciprocal space properties that can be correlated to the experimental location of the so-called Boolchand intermediate phase in these glassy networks. These findings are associated with diffusion anomalies for the parent liquid phase, thereby linking structural and dynamical atomic-scale fingerprints for the onset of rigidity within the network, while also providing a much more complex picture than the one derived from mean-field approaches of stiffness transitions.
  Physical Review Letters 04/2013; 110(16):165501.
• Article: Tracing the Steps of Photoinduced Chemical Reactions in Organic Molecules by Coherent Two-Dimensional Electronic Spectroscopy Using Triggered Exchange

  Stefan Ruetzel, Martin Kullmann, Johannes Buback, Patrick Nuernberger, Tobias Brixner
  Physical Review Letters 04/2013; 110(14):148305.
• Article: DAFNE operation with electron-cloud-clearing electrodes

  D. Alesini, A. Drago, A. Gallo, S. Guiducci, C. Milardi, A. Stella, M. Zobov, S. De Santis, T. Demma, P. Raimondi
  [show abstract] [hide abstract]
  ABSTRACT: The effects of an electron cloud (e-cloud) on beam dynamics are one of the major factors limiting performances of high intensity positron, proton, and ion storage rings. In the electron-positron collider DAΦNE, namely, a horizontal beam instability due to the electron-cloud effect has been identified as one of the main limitations on the maximum stored positron beam current and as a source of beam quality deterioration. During the last machine shutdown in order to mitigate such instability, special electrodes have been inserted in all dipole and wiggler magnets of the positron ring. It has been the first installation all over the world of this type since long metallic electrodes have been installed in all arcs of the collider positron ring and are currently used during the machine operation in collision. This has allowed a number of unprecedented measurements (e-cloud instabilities growth rate, transverse beam size variation, tune shifts along the bunch train) where the e-cloud contribution is clearly evidenced by turning the electrodes on and off. In this Letter we briefly describe a novel design of the electrodes, while the main focus is on experimental measurements. Here we report all results that clearly indicate the effectiveness of the electrodes for e-cloud suppression.
  Physical Review Letters 03/2013; 110:124801.
• Article: Brownian ratchet in a thermal bath driven by Coulomb friction

  A. Gnoli, A. Petri, F. Dalton, G. Gradenigo, G. Pontuale, A. Sarracino, A. Puglisi
  [show abstract] [hide abstract]
  ABSTRACT: The rectification of unbiased fluctuations, also known as the ratchet effect, is normally obtained under statistical non-equilibrium conditions. Here we propose a new ratchet mechanism where a thermal bath solicits the random rotation of an asymmetric wheel, which is also subject to Coulomb friction due to solid-on-solid contacts. Numerical simulations and analytical calculations demonstrate a net drift induced by friction. If the thermal bath is replaced by a granular gas, the well known granular ratchet effect also intervenes, becoming dominant at high collision rates. For our chosen wheel shape the granular effect acts in the opposite direction with respect to the friction-induced torque, resulting in the inversion of the ratchet direction as the collision rate increases. We have realized a new granular ratchet experiment where both these ratchet effects are observed, as well as the predicted inversion at their crossover. Our discovery paves the way to the realization of micro and sub-micrometer Brownian motors in an equilibrium fluid, based purely upon nano-friction.
  Physical Review Letters 03/2013; 110:120601.
• Article: Controllable Optical Phase Shift Over One Radian from a Single Isolated Atom

  A. Jechow, B. G. Norton, S. Händel, V. Blūms, E. W. Streed, D. Kielpinski
  [show abstract] [hide abstract]
  ABSTRACT: Fundamental optics such as lenses and prisms work by applying phase shifts of several radians to incoming light, and rapid control of such phase shifts is crucial to telecommunications. However, large, controllable optical phase shifts have remained elusive for isolated quantum systems. We have used a single trapped atomic ion to induce and measure a large optical phase shift of 1.3±0.1 radians in light scattered by the atom. Spatial interferometry between the scattered light and unscattered illumination light enables us to isolate the phase shift in the scattered component. The phase shift achieves the maximum value allowed by atomic theory over the accessible range of laser frequencies, pointing out new opportunities in microscopy and nanophotonics. Single-atom phase shifts of this magnitude open up new quantum information protocols, in particular long-range quantum phase-shift-keying cryptography.
  Physical Review Letters 03/2013; 110(11):113605.
• Article: Temperature Resistant Optimal Ratchet Transport

  C. Manchein, A. Celestino, M. W. Beims
  [show abstract] [hide abstract]
  ABSTRACT: Stable periodic structures containing optimal ratchet transport, recently found in the parameter space dissipation versus ratchet parameter by [A. Celestino et al. Phys. Rev. Lett. 106 234101 (2011)], are shown to be resistant to reasonable temperatures, reinforcing the expectation that they are essential to explain the optimal ratchet transport in nature. Critical temperatures for their destruction, valid from the overdamping to close to the conservative limits, are obtained numerically and shown to be connected to the current efficiency, given here analytically. A region where thermal activation of the rachet current takes place is also found, and its underlying mechanism is unveiled. Results are demonstrated for a discrete ratchet model and generalized to the Langevin equation with an additional external oscillating force.
  Physical Review Letters 03/2013; 110(11):114102.
• Article: Anomalous fluctuations of currents in Sinai-type random chains with strongly correlated disorder

  Gleb Oshanin, Alberto Rosso, Gregory Schehr
  [show abstract] [hide abstract]
  ABSTRACT: We study properties of a random walk in a generalized Sinai model, in which a quenched random potential is a trajectory of a fractional Brownian motion with arbitrary Hurst parameter H, 0< H <1, so that the random force field displays strong spatial correlations. In this case, the disorder-average mean-square displacement grows in proportion to log^{2/H}(n), n being time. We prove that moments of arbitrary order k of the steady-state current J_L through a finite segment of length L of such a chain decay as L^{-(1-H)}, independently of k, which suggests that despite a logarithmic confinement the average current is much higher than its Fickian counterpart in homogeneous systems. Our results reveal a paradoxical behavior such that, for fixed n and L, the mean square displacement decreases when one varies H from 0 to 1, while the average current increases. This counter-intuitive behavior is explained via an analysis of representative realizations of disorder.
  Physical Review Letters 03/2013; 110:100602.
• Article: Influence Of Toroidal Effets On The Stability Of The Stability Of Internal Kink Mode

  Galvao Sakanaka
  Physical Review Letters 02/2013;
• Article: Raman scattering from plasmons in photoexcited GaP

  J. E. Kardontchik and E. Cohen
  Physical Review Letters 02/2013;
• Article: Measurement of the B-0 and B+ meson lifetimes with fully reconstructed hadronic final states

  B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, [......], Y Pan, R Prepost, IJ Scott, SJ Sekula, JH von Wimmersperg-Toeller, SL Wu, Z Yu, H Zobernig, TMB Kordich, H Neal
  [show abstract] [hide abstract]
  ABSTRACT: The B0 and B+ meson lifetimes have been measured in e+e- annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the ϒ(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B0 and the B+ decay time difference distributions yields τB0 = 1.546±0.032(stat)±0.022(syst) ps, τB+ = 1.673±0.032(stat)±0.023(syst) ps, and τB+/τB0 = 1.082±0.026(stat)±0.012(syst).
  Physical Review Letters 02/2013; 87(20).