Physical Review Letters
Universal Binding and Recoil Corrections to Bound State g Factors in Hydrogenlike Ions
Author(s): Michael I. Eides and Timothy J. S. Martin
The leading relativistic and recoil corrections to bound state g factors of particles with arbitrary spin are calculated. It is shown that these corrections are universal for any spin and depend only on the free particle gyromagnetic ratios. To prove this universality we develop nonrelativistic quan...
[Phys. Rev. Lett. 105, 100402] Published Tue Aug 31, 2010
Dual-Path State Reconstruction Scheme for Propagating Quantum Microwaves and Detector Noise Tomography
Author(s): E. P. Menzel, F. Deppe, M. Mariantoni, M. Á. Araque Caballero, A. Baust, T. Niemczyk, E. Hoffmann, A. Marx, E. Solano, and R. Gross
Quantum state reconstruction of weak propagating microwaves to date requires the use of linear amplifiers. We introduce a theory which, even in the presence of significant amplifier noise, allows one to use these devices for measuring all quadrature moments of propagating quantum microwaves based on...
[Phys. Rev. Lett. 105, 100401] Published Tue Aug 31, 2010
Fluctuations and Scaling in Creep Deformation
Author(s): Jari Rosti, Juha Koivisto, Lasse Laurson, and Mikko J. Alava
The spatial fluctuations of deformation are studied in the creep in Andrade’s power law and the logarithmic phases, using paper samples. Measurements by the digital image correlation technique show that the relative strength of the strain rate fluctuations increases with time, in both creep regimes....
[Phys. Rev. Lett. 105, 100601] Published Mon Aug 30, 2010
Fault Tolerance with Noisy and Slow Measurements and Preparation
Author(s): Gerardo A. Paz-Silva, Gavin K. Brennen, and Jason Twamley
It is not so well known that measurement-free quantum error correction protocols can be designed to achieve fault-tolerant quantum computing. Despite their potential advantages in terms of the relaxation of accuracy, speed, and addressing requirements, they have usually been overlooked since they ar...
[Phys. Rev. Lett. 105, 100501] Published Mon Aug 30, 2010
Hot Brownian Motion
Author(s): Daniel Rings, Romy Schachoff, Markus Selmke, Frank Cichos, and Klaus Kroy
We derive the Markovian description for the nonequilibrium Brownian motion of a heated nanoparticle in a simple solvent with a temperature-dependent viscosity. Our analytical results for the generalized fluctuation-dissipation and Stokes-Einstein relations compare favorably with measurements of lase...
[Phys. Rev. Lett. 105, 090604] Published Thu Aug 26, 2010
Ultrafast Gates for Single Atomic Qubits
Author(s): W. C. Campbell, J. Mizrahi, Q. Quraishi, C. Senko, D. Hayes, D. Hucul, D. N. Matsukevich, P. Maunz, and C. Monroe
We demonstrate single-qubit operations on a trapped atom hyperfine qubit using a single ultrafast pulse from a mode-locked laser. We shape the pulse from the laser and perform a π rotation of the qubit in less than 50 ps with a population transfer exceeding 99% and negligible effects from spontaneou...
[Phys. Rev. Lett. 105, 090502] Published Thu Aug 26, 2010
Relaxation of a High-Energy Quasiparticle in a One-Dimensional Bose Gas
Author(s): Shina Tan, Michael Pustilnik, and Leonid I. Glazman
We evaluate the relaxation rate of high-energy quasiparticles in a weakly interacting one-dimensional Bose gas. Unlike in higher dimensions, the rate is a nonmonotonic function of temperature, with a maximum at the crossover to the state of suppressed density fluctuations. At the maximum, the relaxa...
[Phys. Rev. Lett. 105, 090404] Published Thu Aug 26, 2010
Casimir Repulsion between Metallic Objects in Vacuum
Author(s): Michael Levin, Alexander P. McCauley, Alejandro W. Rodriguez, M. T. Homer Reid, and Steven G. Johnson
We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it wi...
[Phys. Rev. Lett. 105, 090403] Published Thu Aug 26, 2010
Quantum Interference and Entanglement Induced by Multiple Scattering of Light
Author(s): J. R. Ott, N. A. Mortensen, and P. Lodahl
We report on the effects of quantum interference induced by the transmission of an arbitrary number of optical quantum states through a multiple-scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between two o...
[Phys. Rev. Lett. 105, 090501] Published Wed Aug 25, 2010
Intermediate Disorder Regime for Directed Polymers in Dimension 1+1
Author(s): Tom Alberts, Kostya Khanin, and Jeremy Quastel
We introduce a new disorder regime for directed polymers in dimension 1+1 by scaling the inverse temperature β with the length of the polymer n. We scale βn≔βn-α for α≥0. This scaling interpolates between the weak disorder (β=0) and strong disorder regimes (β>0). The fluctuation exponents ζ for t...
[Phys. Rev. Lett. 105, 090603] Published Tue Aug 24, 2010
Exploiting Lattice Potentials for Sorting Chiral Particles
Author(s): David Speer, Ralf Eichhorn, and Peter Reimann
Several ways are demonstrated of how periodic potentials can be exploited for sorting molecules or other small objects which only differ by their chirality. With the help of a static bias force, the two chiral partners can be made to move along orthogonal directions. Time-periodic external forces ev...
[Phys. Rev. Lett. 105, 090602] Published Tue Aug 24, 2010
Spontaneous Pattern Formation in an Antiferromagnetic Quantum Gas
Author(s): Jochen Kronjäger, Christoph Becker, Parvis Soltan-Panahi, Kai Bongs, and Klaus Sengstock
In this Letter we report on the spontaneous formation of surprisingly regular periodic magnetic patterns in an antiferromagnetic Bose-Einstein condensate (BEC). The structures evolve within a quasi-one-dimensional BEC of 87Rb atoms on length scales of a millimeter with typical periodicities of 20…30...
[Phys. Rev. Lett. 105, 090402] Published Tue Aug 24, 2010
Controlled Transport of Matter Waves in Two-Dimensional Optical Lattices
Author(s): Jasur Abdullaev, Dario Poletti, Elena A. Ostrovskaya, and Yuri S. Kivshar
We propose a method for achieving dynamically controllable transport of highly mobile matter-wave solitons in a driven two-dimensional optical lattice. Our numerical analysis based on the mean-field model and the theory based on the time-averaging approach demonstrate that a fast time-periodic rocki...
[Phys. Rev. Lett. 105, 090401] Published Tue Aug 24, 2010
Critical State of the Anderson Transition: Between a Metal and an Insulator
Author(s): Gabriel Lemarié, Hans Lignier, Dominique Delande, Pascal Szriftgiser, and Jean Claude Garreau
Using a three-frequency one-dimensional kicked rotor experimentally realized with a cold atomic gas, we study the transport properties at the critical point of the metal-insulator Anderson transition. We accurately measure the time evolution of an initially localized wave packet and show that it dis...
[Phys. Rev. Lett. 105, 090601] Published Mon Aug 23, 2010
Enhanced and Reduced Atom Number Fluctuations in a BEC Splitter
Author(s): Kenneth Maussang, G. Edward Marti, Tobias Schneider, Philipp Treutlein, Yun Li, Alice Sinatra, Romain Long, Jérôme Estève, and Jakob Reichel
We measure atom number statistics after splitting a gas of ultracold 87Rb atoms in a purely magnetic double-well potential created on an atom chip. Well below the critical temperature for Bose-Einstein condensation Tc, we observe reduced fluctuations down to -4.9 dB below the atom shot noise level....
[Phys. Rev. Lett. 105, 080403] Published Thu Aug 19, 2010
Local Discrimination of Mixed States
Author(s): J. Calsamiglia, J. I. de Vicente, R. Muñoz-Tapia, and E. Bagan
We provide rigorous, efficiently computable and tight bounds on the average error probability of multiple-copy discrimination between qubit mixed states by local operations assisted with classical communication (LOCC). In contrast with the pure-state case, these experimentally feasible protocols per...
[Phys. Rev. Lett. 105, 080504] Published Wed Aug 18, 2010
Limitations on the Attainable Intensity of High Power Lasers
Author(s): A. M. Fedotov, N. B. Narozhny, G. Mourou, and G. Korn
It is shown that even a single e-e+ pair created by a superstrong laser field in vacuum would cause development of an avalanchelike QED cascade which rapidly depletes the incoming laser pulse. This confirms Bohr’s old conjecture that the electric field of the critical QED strength ES=m2c3/eℏ could n...
[Phys. Rev. Lett. 105, 080402] Published Wed Aug 18, 2010
Quantum Cloning for Absolute Radiometry
Author(s): Bruno Sanguinetti, Enrico Pomarico, Pavel Sekatski, Hugo Zbinden, and Nicolas Gisin
In the quantum regime information can be copied with only a finite fidelity. This fidelity gradually increases to 1 as the system becomes classical. In this Letter we show how this fact can be used to directly measure the amount of radiated power. We demonstrate how these principles can be used to b...
[Phys. Rev. Lett. 105, 080503] Published Tue Aug 17, 2010
Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot
Author(s): Jose Garcia Coello, Abolfazl Bayat, Sougato Bose, John H. Jefferson, and Charles E. Creffield
We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the Affleck-Kennedy...
[Phys. Rev. Lett. 105, 080502] Published Tue Aug 17, 2010
Entanglement Entropy and Entanglement Spectrum of the Kitaev Model
Author(s): Hong Yao and Xiao-Liang Qi
In this Letter, we obtain an exact formula for the entanglement entropy of the ground state and all excited states of the Kitaev model. Remarkably, the entanglement entropy can be expressed in a simple separable form S=SG+SF, with SF the entanglement entropy of a free Majorana fermion system and SG ...
[Phys. Rev. Lett. 105, 080501] Published Mon Aug 16, 2010
