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Physical Review A
Physical Review A
provides a dependable resource of worldwide developments in the rapidly
evolving area of atomic, molecular and optical physics and related
fundamental concepts. The journal contains articles on quantum
mechanics including quantum information theory, atomic and molecular
structure and dynamics, collisions and interactions (including
interactions with surfaces and solids), clusters (including
fullerenes), atomic and molecular processes in external fields, matter
waves (including Bose-Einstein condensation) and quantum optics. New
sections on quantum communication, computation, cryptography and matter
waves are growing rapidly. More...
January 26, 2010  The
editors of the APS journals have selected 157 new Outstanding Referees
for 2010, out of more than 42,000 currently active referees. Initiated
in 2008, the highly selective Outstanding Referee program recognizes
scientists who have been exceptionally helpful in assessing manuscripts
for publication in the APS journals. Selections are based on two
decades of records on the number, quality, and timeliness of referee
reports. The 2010 honorees come from 30 different countries, with large
contingents from the US, Germany, UK, Canada, and France. The decisions
were difficult and there are many excellent referees who have yet to be
recognized. By means of the program, APS expresses appreciation to all
referees, whose efforts in peer review not only keep the standards of
the journals at a high level, but in many cases also help authors to
improve the quality and readability of their articles—even those that
are not published by APS. For more information and a sortable listing
of all Outstanding Referees, please visit http://publish.aps.org/OutstandingReferees.
More News/Announcements
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January 11, 2010
Coupled atom cavities can emulate the many-body behavior of condensed matter systems. [Synopsis on Phys. Rev. A 80, 063838 (2009)] Read Article | More Synopses |
January 11, 2010
In the generation of attosecond pulse trains, the polarization state of the driving pulse acts as a tunable gate. [Synopsis on Phys. Rev. A 80, 063837 (2009)] Read Article | More Synopses |
January 4, 2010 As
part of a new APS initiative all APS journal content from 1893 to
present is now hosted on a single platform run by the APS Editorial
Office. In addition, we have added new APS Journal accounts that will
allow us to better integrate all APS services provided to readers,
authors, referees, and members during the coming year while allowing
users to have a more personalized view. This new foundation will allow
APS to move quickly to introduce many new features across all of our
web sites.
Read More | More News/Announcements
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December 1, 2009 On March 3 of this year, the Editors of Physical Review A
sent a survey to over 5700 of our referees and authors in order to
obtain feedback on the journal. We were very pleased with the response
rate of over 30%, and on behalf of the journal we would like to thank
all those who took the time to respond. The purpose of this Editorial
is to report on the results of the survey, and the changes being made
at Physical Review A in response.
Read More | More Editorials
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October 13, 2009 The
first update to REVTeX since 2001 is now available. REVTeX 4.1 includes
bug fixes, improved functionality, and support for a wider range of
journals, including those of the American Institute of Physics (AIP).
REVTEX 4.1 was developed jointly by APS, AIP, and Arthur Ogawa.
Additional work was done by Patrick Daly to incorporate our suggested
improvements into his natbib package to address many new features
concerning bibliographies. For more information, please visit http://authors.aps.org/revtex4/. More News/Announcements
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February 4, 2010
Three papers explain aspects of the size and structure of natural supply networks such as blood vessels and leaf veins.
Read More
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More Focus Articles
|
 Recently published Rapid Communications in Physical Review A.
Fundamental concepts
Dong Zhou and Robert Joynt
For many implementations of quantum computing, 1/f
and other types of broad-spectrum noise are important sources of
decoherence. An important step forward would be the ability to extract
the characteristics of this noise from qubit measurements to see if it
leads to new physical effects. For certain...
[Phys. Rev. A 81, 010103
] Published Thu Jan 28, 2010
Read article
Alioscia Hamma, Daniel A. Lidar, and Simone Severini
Quantum systems with short-range
interactions are known to respect an area law for the entanglement
entropy: The von Neumann entropy S associated to a bipartition scales with the boundary p between the two parts. Here we study the case in which the boundary is a fractal. We consider the topologicall...
[Phys. Rev. A 81, 010102
] Published Wed Jan 27, 2010
Read article
Tomoyuki Morimae
I show relations between superposition of
macroscopically distinct states and entanglement. These relations lead
to the important conclusion that if a state includes superposition of
macroscopically distinct states, the state also includes large
multipartite entanglement in terms of several measures...
[Phys. Rev. A 81, 010101
] Published Mon Jan 25, 2010
Read article
Quantum information
Joshua Combes, Howard M. Wiseman, and A. J. Scott
Feedback control protocols can stabilize
and enhance the operation of quantum devices, however, unavoidable
delays in the feedback loop adversely affect their performance. We
introduce a quantum control methodology, combining open-loop control
with quantum filtering, which is not constrained by feed...
[Phys. Rev. A 81, 020301
] Published Thu Feb 4, 2010
Read article
Philippe Corboz, Glen Evenbly, Frank Verstraete, and Guifré Vidal
We propose an algorithm to simulate
interacting fermions on a two-dimensional lattice. The approach is an
extension of the entanglement renormalization technique [Phys. Rev.
Lett. 99, 220405 (2007)] and the related multiscale entanglement
renormalization ansatz. Benchmark calculations for free and i...
[Phys. Rev. A 81, 010303
] Published Thu Jan 21, 2010
Read article
Alastair Kay and Peter J. Pemberton-Ross
We show how to implement quantum
computation on a system with an intrinsic Hamiltonian by controlling a
limited subset of spins. Our primary result is an efficient control
sequence on a nearest-neighbor XY spin chain through control of a single site and its interaction with its neighbor. Control of ...
[Phys. Rev. A 81, 010301
] Published Wed Jan 6, 2010
Read article
Loïck Magnin, Frédéric Magniez, Anthony Leverrier, and Nicolas J. Cerf
Unconditionally secure bit commitment is
forbidden by quantum mechanics. We extend this no-go theorem to
continuous-variable protocols where both players are restricted to use
Gaussian states and operations, which is a reasonable assumption in
current-state optical implementations. Our Gaussian no-g...
[Phys. Rev. A 81, 010302
] Published Wed Jan 6, 2010
Read article
K. Manouchehri and J. B. Wang
Quantum random walks have received much
interest due to their nonintuitive dynamics, which may hold the key to
a new generation of quantum algorithms. What remains a major challenge
is a physical realization that is experimentally viable and not limited
to special connectivity criteria. We present a...
[Phys. Rev. A 80, 060304
] Published Wed Dec 16, 2009
Read article
Koji Azuma, Naoya Sota, Ryo Namiki, Şahin Kaya Özdemir, Takashi Yamamoto, Masato Koashi, and Nobuyuki Imoto
We propose a realistic protocol to
generate entanglement between quantum memories at neighboring nodes in
hybrid quantum repeaters. Generated entanglement includes only one type
of error, which enables efficient entanglement distillation. In
contrast to the known protocols with such a property, our ...
[Phys. Rev. A 80, 060303
] Published Tue Dec 15, 2009
Read article
Atomic and molecular structure and dynamics
L. V. Skripnikov, A. N. Petrov, A. V. Titov, and N. S. Mosyagin
Recently, the molecular cation PtH+
was suggested as a promising candidate for the experimental search for
the electron electric dipole moment. For estimating the sensitivity of
the experiment on the cation and for interpretation of the experimental
results, it is necessary to calculate an effecti...
[Phys. Rev. A 80, 060501
] Published Thu Dec 10, 2009
Read article
Atomic and molecular collisions and interactions
Colin B. Connolly, Yat Shan Au, S. Charles Doret, Wolfgang Ketterle, and John M. Doyle
Spin relaxation due to atom–atom
collisions is measured for magnetically trapped erbium and thulium
atoms at a temperature near 500 mK. The rate constants for Er–Er and
Tm–Tm collisions are 3.0×10-10 and 1.1×10-10 cm3 s-1, respectively, 2–3 orders of magnitude larger than those observed ...
[Phys. Rev. A 81, 010702
] Published Wed Jan 20, 2010
Read article
Armin Lühr and Alejandro Saenz
Total cross sections for single
ionization and excitation of molecular hydrogen by antiproton impact
are presented over a wide range of impact energies from 1 keV to 6.5
MeV. A nonperturbative time-dependent close-coupling method is applied
to fully treat the correlated dynamics of the electrons. Go...
[Phys. Rev. A 81, 010701
] Published Tue Jan 5, 2010
Read article
Clusters (including fullerenes)
M. Hoener, D. Rolles, A. Aguilar, R. C. Bilodeau, D. Esteves, P. Olalde Velasco, Z. D. Pešić, E. Red, and N. Berrah
We investigated energy and charge
transfer mechanisms as well as fragmentation dynamics in
site-selectively ionized heterogeneous core-shell clusters using a
high-resolution photoelectron-ion coincidence technique. We show that
after inner-shell photoionization, energy or charge is transferred to
ne...
[Phys. Rev. A 81, 021201
] Published Mon Feb 1, 2010
Read article
Atomic and molecular processes in external fields, including interactions with strong fields and short pulses
T. Osipov, Th. Weber, T. N. Rescigno, S. Y.
Lee, A. E. Orel, M. Schöffler, F. P. Sturm, S. Schössler, U. Lenz, T.
Havermeier, M. Kühnel, T. Jahnke, J. B. Williams, D. Ray, A. Landers,
R. Dörner, and A. Belkacem
We report a kinematically complete experiment on the production of CO+
autoionizing states following photoionization of carbon monoxide below
its vertical double-ionization threshold. Momentum imaging spectroscopy
is used to measure the energies and body-frame angular distributions of
both photo- an...
[Phys. Rev. A 81, 011402
] Published Wed Jan 27, 2010
Read article
G. Heinze, A. Rudolf, F. Beil, and T. Halfmann
We report on storage of images in atomic
coherences driven by electromagnetically induced transparency in a
doped solid. We demonstrate image storage times up to the regime of
milliseconds (i.e., more than two orders of magnitude larger than in
gaseous media). Our data also reveal an improvement in ...
[Phys. Rev. A 81, 011401
] Published Mon Jan 25, 2010
Read article
Kai-Jun Yuan, HuiZhong Lu, and André D. Bandrauk
Numerical solution of the time-dependent Schrödinger equation for a two-dimension model of H2
ionization by intense ultrashort (few cycles) extreme ultraviolet (XUV)
laser pulses are presented to compare linear and circular polarization
angular distributions for aligned molecules. Both ground (X...
[Phys. Rev. A 80, 061403
] Published Thu Dec 17, 2009
Read article
Matter waves and collective properties of cold atoms and molecules
William Schneider and Mohit Randeria
We show that the universal 1/k4 tail in the momentum distribution of dilute Fermi gases implies that the spectral function A(k,ω) must have weight below the chemical potential for large momentum k≫kF, with observable consequences in radio-frequency spectroscopy experiments. We find that this inco...
[Phys. Rev. A 81, 021601
] Published Wed Feb 3, 2010
Read article
J. K. Freericks, M. M. Maśka, Anzi Hu, Thomas M. Hanna, C. J. Williams, P. S. Julienne, and R. Lemański
Ultracold ground-state dipolar 40K87Rb
molecules recently have been produced in a loose harmonic trap by
employing a magnetic field sweep across a Feshbach resonance followed
by stimulated Raman adiabatic passage [K.-K. Ni , Science 322, 231
(2008)]. The overall experimental efficiency for molecule ...
[Phys. Rev. A 81, 011605
] Published Thu Jan 28, 2010
Read article
T. Shi, Yue Yu, and C. P. Sun
We study supersymmetric (SUSY) responses to a photoassociation (PA) process in a mixture of Bose molecules b and Fermi atoms f which turn to mutual superpartners for a set of proper parameters. We consider the molecule b to be a bound state of the atom f and another Fermi atom F with different speci...
[Phys. Rev. A 81, 011604
] Published Mon Jan 25, 2010
Read article
Alexander Mering and Michael Fleischhauer
The ground-state phase diagram of
mixtures of spin polarized fermions and bosons in a 1D periodic lattice
is discussed in the limit of large fermion hopping and half filling of
the fermions. Numerical simulations performed with the density matrix
renormalization group (DMRG) show in addition to boso...
[Phys. Rev. A 81, 011603
] Published Wed Jan 20, 2010
Read article
R. G. Dall, S. S. Hodgman, M. T. Johnsson, K. G. H. Baldwin, and A. G. Truscott
Ultracold atoms whose de Broglie
wavelength is of the same order as an extended confining potential can
experience waveguiding along the potential. When the transverse kinetic
energy of the atoms is sufficiently low, they can be guided in the
lowest order mode of the confining potential by analogy w...
[Phys. Rev. A 81, 011602
] Published Thu Jan 7, 2010
Read article
Manuel Valiente, David Petrosyan, and Alejandro Saenz
We pursue three-body bound states in a
one-dimensional tight-binding lattice described by the Bose-Hubbard
model with strong on-site interaction. Apart from the simple strongly
bound “trimer” state corresponding to all three particles occupying the
same lattice site, we find two novel kinds of w...
[Phys. Rev. A 81, 011601
] Published Mon Jan 4, 2010
Read article
Jean-Sébastien Caux, Antoine Klauser, and Jeroen van den Brink
We study the interplay of quantum
statistics, strong interactions, and finite temperatures in the
two-component (spinor) Bose gas with repulsive delta-function
interactions in one dimension. Using the Thermodynamic Bethe Ansatz, we
obtain the equation of state, population densities, and local densit...
[Phys. Rev. A 80, 061605
] Published Mon Dec 14, 2009
Read article
A. Emmert, A. Lupaşcu, M. Brune, J.-M. Raimond, S. Haroche, and G. Nogues
Recently demonstrated superconducting
atom chips provide a platform for trapping atoms and coupling them to
solid-state quantum systems. Controlling these devices requires a full
understanding of the supercurrent distribution in the trapping
structures. For type-II superconductors, this distribution...
[Phys. Rev. A 80, 061604
] Published Thu Dec 10, 2009
Read article
Quantum optics, physics of lasers, nonlinear optics, classical optics
Luc Bergé, Christian Köhler, and Stefan Skupin
Compression of UV femtosecond laser
pulses focused into a gas cell filled with Xe is reported numerically.
With a large negative Kerr index and normal dispersion, Xe promotes
temporal modulational instability (MI), which can be monitored to
shorten ~100 fs pulses to robust, singly peaked waveforms e...
[Phys. Rev. A 81, 011805
] Published Wed Jan 27, 2010
Read article
Iver Brevik and Simen Å. Ellingsen
We show, by means of simple model
calculations, how a weak laser beam sent though an optical fiber exerts
a transverse radiation force if there is an azimuthal asymmetry present
in the fiber such that one side has a slightly different refractive
index than the other. The refractive index difference ...
[Phys. Rev. A 81, 011806
] Published Wed Jan 27, 2010
Read article
Ulf Leonhardt and Thomas G. Philbin
Maxwell’s fish eye has been known to be a perfect lens within the validity range of ray optics since 1854.
Solving Maxwell’s equations, we show that the fish-eye lens in three
dimensions has unlimited resolution for electromagnetic waves.
[Phys. Rev. A 81, 011804
] Published Mon Jan 25, 2010
Read article
Daniele Faccio, Carles Serrat, José M. Cela, Albert Farrés, Paolo Di Trapani, and Jens Biegert
The process of high-order harmonic
generation in gases is numerically investigated in the presence of a
few-cycle pulsed-Bessel-beam pump, featuring a periodic modulation in
the peak intensity due to large carrier-envelope-phase mismatch. A
two-decade enhancement in the conversion efficiency is obse...
[Phys. Rev. A 81, 011803
] Published Fri Jan 8, 2010
Read article
C. Schuck, F. Rohde, N. Piro, M. Almendros, J. Huwer, M. W. Mitchell, M. Hennrich, A. Haase, F. Dubin, and J. Eschner
We observe the interaction of a single
trapped calcium ion with single photons produced by a narrow-band,
resonant down-conversion source [A. Haase , Opt. Lett. 34, 55 (2009)],
employing a quantum jump scheme. Using the temperature dependence of
the down-conversion spectrum and the tunability of the...
[Phys. Rev. A 81, 011802
] Published Wed Jan 6, 2010
Read article
Georg Heinrich, J. G. E. Harris, and Florian Marquardt
The motion of micro- and nanomechanical
resonators can be coupled to electromagnetic fields. Such
optomechanical setups allow one to explore the interaction of light and
matter in a new regime at the boundary between quantum and classical
physics. We propose an approach to investigate nonequilibrium...
[Phys. Rev. A 81, 011801
] Published Tue Jan 5, 2010
Read article
Recently published articles in Physical Review A. See the current issue for more.
Fundamental concepts
A. O. Sushkov, S. Eckel, and S. K. Lamoreaux
We propose to use ferroelectric (Eu,Ba)TiO3
ceramics just above their magnetic ordering temperature for a sensitive
electron electric-dipole-moment search. We have synthesized a number of
such ceramics with various europium concentrations and measured their
properties relevant for such a search: per...
[Phys. Rev. A 81, 022104
] Published Fri Feb 5, 2010
Read article
D. Sokolovski and R. Sala Mayato
We analyze a system in which, due to
entanglement between the spin and spatial degrees of freedom, the
reduced transmitted state has the shape of the freely propagating pulse
translated in the complex coordinate plane. In the case an apparently
“superluminal” advancement of the pulse, the delay ...
[Phys. Rev. A 81, 022105
] Published Fri Feb 5, 2010
Read article
Quantum information
Zhi-Xin Chen, Zheng-Wei Zhou, Xingxiang Zhou, Xiang-Fa Zhou, and Guang-Can Guo
We propose a scheme to simulate one-dimensional XXZ-type
Heisenberg spin models with competing interactions between nearest
neighbors (NNs) and next NNs in photon-coupled microcavities. Our
scheme exploits the rich resources and flexible controls available in
such a system to realize arbitrarily adj...
[Phys. Rev. A 81, 022303
] Published Fri Feb 5, 2010
Read article
Tomoyuki Morimae
We investigate low-temperature coherence properties of the Z2
quantum memory which is capable of storing the information of a single
logical qubit. We show that the memory has superposition of
macroscopically distinct states for some values of a control parameter
and at sufficiently low temperature ...
[Phys. Rev. A 81, 022304
] Published Fri Feb 5, 2010
Read article
I. Serban, M. I. Dykman, and F. K. Wilhelm
We investigate the relaxation of a
superconducting qubit for the case when its detector, the Josephson
bifurcation amplifier, remains latched in one of its two (meta)stable
states of forced vibrations. The qubit relaxation rates are different
in different states. They can display strong dependence o...
[Phys. Rev. A 81, 022305
] Published Fri Feb 5, 2010
Read article
Atomic and molecular collisions and interactions
Jessica R. Francis-Staite, Brett A. Schmerl, Michael J. Brunger, H. Kato, and Stephen J. Buckman
Experimental results are reported for elastic differential and integral cross sections for electrons scattering from CF3I.
These measurements were made at ten incident electron energies in the
range 10–50 eV, with a scattered electron angular range of 20°–135°. Where possible, comparison is m...
[Phys. Rev. A 81, 022704
] Published Mon Feb 8, 2010
Read article
Goulven Quéméner and John L. Bohn
We use the quantum threshold laws
combined with a classical capture model to provide an analytical
estimate of the chemical quenching cross sections and rate coefficients
of two colliding particles at ultralow temperatures. We apply this
quantum threshold model (QT model) to indistinguishable fermio...
[Phys. Rev. A 81, 022702
] Published Thu Feb 4, 2010
Read article
Xiang Gao, Xiao-Ying Han, Lan Voky, Nicole Feautrier, and Jia-Ming Li
The collision cross sections of sodium
from the ground state to the first four excited states at the incident
energy ranging from 0 to 5.4 eV are calculated using the R-matrix
method. The convergences of the cross sections are checked
systematically by using four sets of high-quality target states, ...
[Phys. Rev. A 81, 022703
] Published Thu Feb 4, 2010
Read article
Photon, electron, atom, and molecule interactions with solids and surfaces
Allan H. Sørensen
The emission of electromagnetic radiation
by relativistic bare heavy ions penetrating ordinary matter is
investigated. Our main aim is to determine the bremsstrahlung
which we define as the radiation emitted when the projectile does not
break up. It pertains to collisions without nuclear contact (â€...
[Phys. Rev. A 81, 022901
] Published Mon Feb 8, 2010
Read article
Clusters (including fullerenes)
Takeshi Kai
Single-differential and integral cross
sections for electron-impact ionization of the C atom and its ions were
calculated with the binary-encounter-dipole model [Y.-K. Kim and M. E.
Rudd, Phys. Rev. A 50, 3954 (1994)] to study the distribution of
free-electron energies in carbon clusters after being...
[Phys. Rev. A 81, 023201
] Published Fri Feb 5, 2010
Read article
Atomic and molecular processes in external fields, including interactions with strong fields and short pulses
Emilio Ignesti, Roberto Buffa, Lorenzo Fini, Emiliano Sali, Marco V. Tognetti, and Stefano Cavalieri
We report the experimental observation of
an optically controllable shift of the central frequency of a laser
pulse, using a scheme based on dynamical electromagnetically induced
transparency. This is evidence of frequency shift controllable by a
coherent process. Original theoretical results are in...
[Phys. Rev. A 81, 023405
] Published Mon Feb 8, 2010
Read article
S. Wüster, J. Stanojevic, C. Ates, T. Pohl, P. Deuar, J. F. Corney, and J. M. Rost
We show that Rydberg states in an
ultracold gas can be excited with strongly preferred nearest-neighbor
distance if densities are well below saturation. The scheme makes use
of an echo sequence in which the first half of a laser pulse excites
Rydberg states while the second half returns atoms to the...
[Phys. Rev. A 81, 023406
] Published Mon Feb 8, 2010
Read article
Tomoya Akatsuka, Masao Takamoto, and Hidetoshi Katori
We present detailed analyses of our recent experiment on the three-dimensional (3D) optical lattice clock with bosonic 88Sr
atoms in which the collisional frequency shift was suppressed by
applying a single-occupancy lattice. Frequency shifts in magnetically
induced spectroscopy on the 1S0–3P0 clo...
[Phys. Rev. A 81, 023402
] Published Thu Feb 4, 2010
Read article
Brian Mischuck, Ivan H. Deutsch, and Poul S. Jessen
Coherent transport of atoms trapped in an
optical lattice can be controlled by microwave-induced spin flips that
correlate with site-to-site hopping. We study the controllability of
homogeneous one-dimensional systems of noninteracting atoms in the
absence of site addressability. Given these restric...
[Phys. Rev. A 81, 023403
] Published Thu Feb 4, 2010
Read article
Lih-King Lim, Andreas Hemmerich, and C. Morais Smith
A time-dependent optical lattice with
staggered particle current in the tight-binding regime was considered
that can be described by a time-independent effective lattice model
with an artificial staggered magnetic field. The low-energy description
of a single-component fermion in this lattice at hal...
[Phys. Rev. A 81, 023404
] Published Thu Feb 4, 2010
Read article
Matter waves and collective properties of cold atoms and molecules
B. Olmos, R. González-Férez, and I. Lesanovsky
The collective excitation of a gas of
highly excited atoms confined to a large spacing ring lattice is
studied, where the ground and the excited states are resonantly coupled
via a laser field. Attention is focused on the regime where the
interaction between the highly excited atoms is very weak in ...
[Phys. Rev. A 81, 023604
] Published Mon Feb 8, 2010
Read article
J. Brand, T. J. Haigh, and U. Zülicke
We revisit recent claims about the
instability of nonrotating tunnel coupled annular Bose-Einstein
condensates leading to the emergence of angular momentum Josephson
oscillation [Phys. Rev. Lett. 98, 050401 (2007)]. It was predicted that
all stationary states with uniform density become unstable in ...
[Phys. Rev. A 81, 025602
] Published Mon Feb 8, 2010
Read article
Predrag Nikolić
By analyzing vortex lattices, re-entrant
Cooper pairing, and Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states in a
single theoretical framework, we explore how vortices and spin textures
join to protect superconductivity against large magnetic fields. We use
a rapidly rotating ultracold gas of fermion...
[Phys. Rev. A 81, 023601
] Published Fri Feb 5, 2010
Read article
Ching-Kit Chan, Congjun Wu, Wei-Cheng Lee, and S. Das Sarma
We study the Fermi liquid properties of
the cold atomic dipolar Fermi gases with the explicit dipolar
anisotropy using perturbative approaches. Due to the explicit dipolar
anisotropy, Fermi surfaces exhibit distortions of the dr2-3z2 type in three dimensions and of the dx2-y2 type in two dimensions....
[Phys. Rev. A 81, 023602
] Published Fri Feb 5, 2010
Read article
Pekko Kuopanportti, Emil Lundh, Jukka A. M. Huhtamäki, Ville Pietilä, and Mikko Möttönen
Motivated by a recent demonstration of
cyclic addition of quantized vorticity into a Bose-Einstein condensate,
the vortex pump, we study dynamical instabilities and core sizes of
giant vortices. The core size is found to increase roughly as a
square-root function of the quantum number of the vortex,...
[Phys. Rev. A 81, 023603
] Published Fri Feb 5, 2010
Read article
Quantum optics, physics of lasers, nonlinear optics, classical optics
Marco V. Tognetti, Emiliano Sali, Stefano Cavalieri, and Roberto Buffa
We present a theoretical analysis of a
new scheme for temporal retardation combined with temporal compression
of weak laser pulses, optically controlled by the presence of one
additional light pulse. A realistic realization of this scheme in hot
Rb is discussed, showing that a large range of values ...
[Phys. Rev. A 81, 023807
] Published Mon Feb 8, 2010
Read article
Paul Kinsler
I derive unidirectional wave equations
for fields propagating in materials with both electric and magnetic
dispersion and nonlinearity. The derivation imposes no conditions on
the pulse profile except that the material modulates the propagation
slowly, that is, that loss, dispersion, and nonlinearit...
[Phys. Rev. A 81, 023808
] Published Mon Feb 8, 2010
Read article
Ancemma Joseph and K. Porsezian
We analyze the dynamics of propagation of
a Gaussian light pulse through a medium having a negative index of
refraction employing the recently reported projection operator
technique. The governing modified nonlinear Schrödinger equation,
obtained by taking into account the Drude dispersive model, i...
[Phys. Rev. A 81, 023805
] Published Thu Feb 4, 2010
Read article
James Owen Weatherall and Christopher P. Search
Transparent media exhibiting anomalous
dispersion have been of considerable interest since Wang, Kuzmich, and
Dogariu [Nature 406, 277 (2000)] first observed light propagate with
superluminal and negative group velocities without absorption. Here, we
propose an atomic model exhibiting these properti...
[Phys. Rev. A 81, 023806
] Published Thu Feb 4, 2010
Read article
Papers recently accepted for publication in Physical Review A (view more).
Fundamental concepts
Minimum detection efficiencies for a loophole free observable asymmetric Bell type test
G. Garbarino
We discuss the problem of finding the
most favorable conditions for closing the detection loophole in a test
of local realism with a Bell inequality. For a generic non-maximally
entangled two-qubit state and two incompabible bases to be adopted for
alternative measurements of two observables, [^a] and [^b], on each
party we apply Hardy's proof of non-locality without inequality and
derive an Eberhard-like inequality. For an infinity of non-maximally
entangled states we find that it is possible to refute local realism by
requiring perfect detection efficiency for only one of the two
observables, say [^b], to be measured on each party: the test is free
from the detection loophole for any value of the detection efficiency
corresponding to the other observable, [^a]. The maximum tolerable
noise in such loophole-free observable-asymmetric test is also
evaluated.
Accepted Mon Feb 8, 2010
Quantum information
Geometric measures of entanglement
K. Uyanik and S. Turgut
The geometric measure of entanglement,
which expresses the minimum distance to product states, has been
generalized to distances to sets that remain invariant under the
stochastic reducibility relation. For each such set, an associated
entanglement monotone can be defined. The explicit analytical forms of
these measures are obtained for bipartite entangled states. Moreover,
the three qubit case is discussed and argued that the distance to the W
states is a new monotone.
Accepted Fri Feb 5, 2010
Quantum Merlin-Arthur complete problems for stoquastic Hamiltonians and Markov matrices
Stephen P. Jordan, David Gosset and Peter J. Love
We show that finding the lowest
eigenvalue of a 3-local symmetric stochastic matrix is QMA-complete. We
also show that finding the highest energy of a stoquastic Hamiltonian
is QMA-complete and that adiabatic quantum computation using certain
excited states of a stoquastic Hamiltonian is universal. We also show
that adiabatic evolution in the ground state of a stochastic
frustration free Hamiltonian is universal. Our results give a new
QMA-complete problem arising in the classical setting of Markov chains,
and new adiabatically universal Hamiltonians that arise in many
physical systems.
Accepted Fri Feb 5, 2010
Entanglement and perfect local operations and classical communication discrimination of a class of multiqubit states
Somshubhro Bandyopadhyay
It is shown that while entanglement
ensures difficulty in discriminating a set of mutually orthogonal
states perfectly by local operations and classical communication
(LOCC), entanglement content does not. In particular, for a class of
entangled multi-qubit states, the maximum number of perfectly LOCC
distinguishable orthogonal states is shown to be independent of the
average entanglement of the states, and the spatial configuration with
respect to which LOCC operations may be carried out. It is also pointed
out that for this class, the make-up of an ensemble, that is, whether
it consists only of entangled states or is a mix of both entangled and
product states, determines the maximum number of perfectly
distinguishable states.
Accepted Fri Feb 5, 2010
Necessary condition for the quantum adiabatic approximation
S. Boixo and R. D. Somma
A gapped quantum system that is
adiabatically perturbed remains approximately in its eigenstate after
the evolution. We prove that, for constant gap, general quantum
processes that approximately prepare the final eigenstate require a
minimum time proportional to the ratio of the length of the eigenstate
path to the gap. Thus, no rigorous adiabatic condition can yield a
smaller cost. We also give a necessary condition for the adiabatic
approximation that depends on local properties of the path, which is
appropriate when the gap varies.
Accepted Fri Feb 5, 2010
Decoherence in one dimensional quantum walk
Mostafa Annabestani, Seyed Javad Akhtarshenas and Mohamad Reza Abolhassani
In this paper we study decoherence in the
discrete-time quantum walk on the line. We generalize the method of
decoherent coin quantum walk, introduced by Brun et al [Phys. Rev. A
67, 32304 (2003)]. Our analytical expressions are applicable for all
kinds of decoherence. As an example of the coin-position decoherence,
we study the broken line quantum walk and compare our results with the
numerical one. We also show that our analytical results reduce to the
Brun formalism when only the coin is subjected to decoherence.
Accepted Thu Feb 4, 2010
Atomic and molecular structure and dynamics
Millimeter wave spectroscopy and multichannel
quantum defect-theory analysis of high Rydberg states of xenon: The
hyperfine structure of ^{129}Xe^{+} and ^{131}Xe^{+}
Martin Schafer, Matthias Raunhardt and Frederic Merkt
Millimeter-wave transitions between
high-n Rydberg states of several isotopes of xenon have been recorded
at sub-MHz resolution. The fine- and, for 129Xe and 131Xe, the
hyperfine structures of s, p, d, and f Rydberg states with principal
quantum number in the range 52 n 64 have been determined from
combination differences and analyzed using multichannel quantum defect
theory. Improved eigenquantum defects and channel interaction
parameters for the odd and even parity Rydberg states of xenon and the
hyperfine structure of the 2P3/2 ground state of 129Xe+ and 131Xe+ have
been obtained. Nearly degenerate p and d fine or hyperfine levels are
very easily mixed by even weak stray electric fields.
Accepted Thu Feb 4, 2010
Final state spectrum of ^{3}He after \beta^{-} decay of tritium anions T^{-}
Alexander Stark and Alejandro Saenz
The final-state spectrum of b decaying
tritium anions \Tmin was calculated. The wavefunctions describing the
initial \Tmin ground state and the final \Hel states were obtained by
the full configuration-interaction method. The transition probability
was calculated within the sudden approximation. The transition
probability into the electronic continuum is extracted from the
complex-scaled resolvent and is shown to converge for very
high-energies to an approximate analytical model probability
distribution.
Accepted Thu Feb 4, 2010
Atomic and molecular collisions and interactions
Molecular orientation effect on the
differential cross sections for the electron impact double ionization
of oriented water molecules
C. Champion, D. Oubaziz, H. Aouchiche, Yu. V. Popov and C. Dal Cappello
Double ionization of isolated water
molecules fixed in space is here investigated in a theoretical approach
based on the first Born approximation. Secondary electron angular
distributions are reported for particular (e,3e) kinematical conditions
and compared in terms of shape and magnitude. Strong dependence of the
five-fold differential cross sections on the molecular target
orientation is clearly observed in (e,3-1e) as well as (e,3e) channels.
Furthermore, for the major part of the kinematics considered, we
identified the different mechanisms involved in the double ionization
of water molecule, namely, the direct shake-off process as well as the
two-step1 process. They are both discussed and analyzed with respect to
the molecular target orientation.
Accepted Fri Feb 5, 2010
Atomic and molecular processes in external fields, including interactions with strong fields and short pulses
Mechanisms of infrared laser-assisted atomic ionization by attosecond pulses
X. M. Tong, P. Ranitovic, C. L. Cocke and N. Toshima
We propose a mechanism to understand the
infrared (IR) laser assisted atomic ionization by attosecond pulses
(AP). Atomic structures in an IR laser field are described by Floquet
states and atoms can be ionized to a Floquet state by a single AP
through differen Floquet components. The interference of ionization
through different Floquet components results in the oscillation of the
ionization yield as a function of the arriving time of the AP. The
proposed mechanism explains the recent experimental observations
[Johnsson et al., PRL 99 (2007) 233001]. Furthermore, we find that for
a specified photoelectron energy, the ionization yield always
oscillates as a function of the relative phase between the AP and the
IR laser for both helium and argon atoms.
Accepted Mon Feb 8, 2010
Three dimensional lattice of ion traps
K. Ravi, Seunghyun Lee, Arijit Sharma, Tridib Ray, G. Werth and S. A. Rangwala
We propose an ion trap configuration,
which by symmetry is three dimensionally frequency degenerate. This
fundamental trap configuration can be stacked together in a three
dimensional simple cubic arrangement. The isolated trap as well as the
extended array of ion traps are characterized for different locations
in the lattice, illustrating the robustness of the lattice of traps
concept. Ease in the addressing of ions at each lattice site,
individually or simultaneously, makes this system naturally suitable
for a number of experiments. Application of this trap to precision
spectroscopy, quantum information processing and the study of few
particle interacting system are discussed.
Accepted Mon Feb 8, 2010
Matter waves and collective properties of cold atoms and molecules
Matter wave turbulence: Beyond kinetic scaling
Christian Scheppach, Jurgen Berges and Thomas Gasenzer
Turbulent scaling phenomena are studied
in an ultracold Bose gas away from thermal equilibrium. Fixed points of
the dynamical evolution are characterized in terms of universal scaling
exponents of correlation functions. The scaling behavior is determined
analytically in the framework of quantum field theory, using a
nonperturbative approximation of the two-particle irreducible effective
action. While perturbative Kolmogorov scaling is recovered at higher
energies, scaling solutions with anomalously large exponents arise in
the infrared regime of the turbulence spectrum. The extraordinary
enhancement in the momentum dependence of long-range correlations could
be experimentally accessible in dilute ultracold atomic gases. Such
experiments have the potential to provide insight into dynamical
phenomena directly relevant also in other present-day focus areas like
heavy-ion collisions and early-universe cosmology.
Accepted Mon Feb 8, 2010
Decay of a quantum vortex: Test of nonequilibrium theories for warm Bose Einstein condensates
S. J. Rooney, A. S. Bradley and P. B. Blakie
The decay of a vortex from a non-rotating
high temperature Bose-Einstein condensate (BEC) is modeled using the
stochastic projected Gross-Pitaevskii equation (SPGPE). In order to
exploit the tunability of temperature in SPGPE theory while maintaining
the total atom number constant, we develop a simple and accurate
Hartree-Fock method to estimate the SPGPE parameters for systems close
to thermal equilibrium. We then calculate the lifetime of a vortex
using three classical field theories that describe vortex decay in
different levels of approximation. The SPGPE theory is shown to give
the most complete description of the decay process, predicting
significantly shorter vortex lifetimes than the alternative theories.
Using the SPGPE theory to simulate vortex decay for a trapped gas of
5times;105 87Rb atoms, we calculate a vortex lifetime [`t] that
decreases linearly with temperature, falling in the range 20 s >
[`t] > 1.5s corresponding to the temperature range 0.78Tc T 0.93Tc.
The vortex lifetimes calculated provide a lower bound for the lifetime
of a persistent current with unit winding number in our chosen trap
geometry, in the limit of vanishing vortex pinning potential.
Accepted Fri Feb 5, 2010
Spinor condensate of ^{87}Rb as a dipolar gas
Tomasz Swislocki, Miroslaw Brewczyk, Mariusz Gajda and Kazimierz Rzazewski
We consider a spinor condensate of 87Rb
atoms in the F=1 hyperfine state confined in an optical dipole trap.
Putting initially all atoms in the mF=0 component we find that the
system evolves towards a state of thermal equilibrium with kinetic
energy equally distributed among all magnetic components. We show that
this process is dominated by the dipolar interaction of magnetic spins
rather than spin mixing contact potential. Our results show that
because of a dynamical separation of magnetic components, the spin
mixing dynamics in the 87Rb condensate is governed by the dipolar
interaction which plays no role in a single component rubidium system
in a magnetic trap.
Accepted Fri Feb 5, 2010
BCS BEC crossover with unequal mass fermions
Roberto B. Diener and Mohit Randeria
We investigate the crossover from BCS
pairing to molecular BEC in an atomic gas with two fermion species with
masses m\up m\dn tuned through a Feshbach resonance. We present results
for the T=0 equation of state as a function of the scattering length
including the effects of Gaussian fluctuations about the mean field
ground state. We compute the ground state energy as a function of
m\up/m\dn at unitarity and find excellent agreement with the quantum
Monte Carlo result for m\up/m\dn = 6.67 for a 40K-6Li mixture. We show
that the dimer scattering length in the BEC limit as a function of
m\up/m\dn compares well with exact four-body results of Petrov et al.
We also derive the condition for trapping frequencies to obtain an
unpolarized gas in a harmonic trap.
Accepted Fri Feb 5, 2010
Quantum optics, physics of lasers, nonlinear optics, classical optics
Effective nonlinear Hamiltonians in dielectric media
J. A. Crosse and Stefan Scheel
We derive an effective Hamiltonian for
the nonlinear process of parametric down conversion in the presence of
absorption. Based upon the Green function method for quantizing the
electromagnetic field, we first set up Heisenberg's equations of motion
for a single atom driven by an external electric field and in the
presence of an absorbing dielectric material. The equations of motion
are then solved to second order in perturbation theory which, in
rotating-wave approximation, yields the standard effective interaction
Hamiltonian known from free-space nonlinear optics. In a second step,
we derive the local-field corrected Hamiltonian for an atom embedded in
a dielectric host medium, i.e. a nonlinear crystal. Here we show that
the resulting effective Hamiltonian is found to be trilinear in the
electric and noise polarization fields, and is thus capable of
describing nonlinear noise processes. Furthermore, it reduces to the
phenomenological nonlinear Hamiltonian for the cases where absorption,
and hence the noise polarization field, vanishes.
Accepted Mon Feb 8, 2010
Optical injection in semiconductor ring lasers
W. Coomans, S. Beri, G. Van der Sande, L. Gelens and J. Danckaert
We theoretically investigate optical
injection in semiconductor ring lasers and disclose several dynamical
regimes. Through numerical simulations and bifurcation continuation,
two separate parameter regions in which two different injection-locked
solutions coexist are revealed, in addition to a region in which a
frequency-locked limit cycle coexists with an injection-locked
solution. Finally, an anti-phase chaotic regime without the involvement
of any carrier dynamics is revealed. Parallels are drawn with the onset
of chaos in the periodically forced Duffing oscillator.
Accepted Mon Feb 8, 2010
Band gap boundaries and fundamental solitons in complex two dimensional nonlinear lattices
Mark J. Ablowitz, Nalan Antar, Ilkay Bakirtas and Boaz Ilan
Nonlinear Schr#246;dinger (NLS) equation
with external potentials (lattices) possessing crystal and quasicrystal
structures are studied. The fundamental solitons and band gaps are
computed using a spectral fixed-point numerical scheme. Nonlinear and
linear stability properties of the fundamental solitons are
investigated by direct simulations and the linear stability properties
of the fundamental solitons are confirmed by analysis the linearized
eigenvalue problem.
Accepted Mon Feb 8, 2010
Optical angular momentum: Multipole transitions and photonics
David L. Andrews
The premise that multipolar decay should
produce photons uniquely imprinted with a measurably corresponding
angular momentum is shown in general to be untrue. To assume a
one-to-one correlation between the transition multipoles involved in
source decay and detector excitation is to impose a generally
unsupportable one-to-one correlation between the multipolar form of
emission transition and a multipolar character for the detected field.
It is specifically proven impossible to determine without ambiguity, by
use of any conventional detector, and for any photon emitted through
the non-dipolar decay of an atomic excited state, a unique multipolar
character for the transition associated with its generation. Consistent
with the angular quantum uncertainty principle, removal of a detector
from the immediate vicinity of the source produces a decreasing angular
uncertainty in photon propagation direction, reflected in an increasing
range of integer values for the measured angular momentum. In such a
context it follows that when the decay of an electronic excited state
occurs by an electric quadrupolar transition, for example, any
assumption that the radiation so produced is conveyed in the form of
"quadrupole photons" is experimentally unverifiable. The results of the
general proof based on irreducible tensor analysis invite experimental
verification, and they signify certain limitations on quantum optical
data transmission.
Accepted Mon Feb 8, 2010
Slow light transmission in one dimensional periodic structures
O. del Barco and M. Ortuno
We have analyzed the transmission
properties of pulses through one-dimensional periodic structures in
order to systematically explore the best conditions to achieve the
maximum delay with the minimum possible distortion. In the absence of
absorption and no layer variation, the transmission coefficient tN can
be well approximated by a sum of Lorentzian resonances. The ratio
between their width Gr and their separation Dwr is a crucial parameter
to characterize the distortion of the transmitted pulse. For typical
values of the parameters used in telecommunications and high index of
refraction contrasts n2 / n1, the distortion of the transmitted pulse
is unacceptably large for frequencies near the edge of the transmission
window. We estimate fractional delays achievables in terms of the
central frequency used and the pulse bandwidth.
Accepted Mon Feb 8, 2010
Diode laser system for high resolution
spectroscopy of the ^{2}S_{1/2} \rightarrow {^{2}F_{7/2}} octupole
transition in ^{171}Yb^{+}
I. Sherstov, M. Okhapkin, B. Lipphardt, Chr. Tamm and E. Peik
A diode-laser system at 467 nm is built
in order to drive the 2S1/2 2F7/2 electric octupole transition at 467
nm in 171Yb+. The frequency of the laser is stabilized to a reference
cavity made of ultra low expansion glass and is demonstrated to have a
relative instability of better than 2times;10-15 at 1 s and a stable
linear drift rate with variations below 10 mHz/s over several hours.
The system is applied for spectroscopy of a single trapped laser-cooled
171Yb+ ion. We obtain excitation spectra of the octupole transition
with a resonant excitation probability of about 65% and an essentially
Fourier transform-limited resolution of 13 Hz.
Accepted Fri Feb 5, 2010
Controlling enhancement and suppression of four wave mixing via polarized light
Cha Lingbiao, Yanpeng Zhang, Zhiqiang Nie, Yig Duang, Ruimin Wang, Jianping Song and Min Xiao
We show that the four-wave mixing (FWM)
processes in a multi-Zeeman level atomic system can be enhanced and
suppressed by changing the polarization of one of the pump beams.
Different polarization states of the pump beams will act on different
transition pathways among the multi-Zeeman levels with different
transition strengths, which affect the FWM efficiencies. An additional
dress field applied to the adjacent transition can cause energy level
splitting and therefore control the enhancement and suppression of the
FWM processes in the system. The experimental results are in good
agreement with our theoretical calculations.
Accepted Fri Feb 5, 2010
Unified kinetic formulation of incoherent waves propagating in nonlinear media with noninstantaneous response
Josselin Garnier and Antonio Picozzi
This paper presents a unified kinetic
formulation of partially coherent nonlinear optical waves propagating
in a noninstantaneous response Kerr medium. We derive a kinetic
equation that combines the weak Langmuir turbulence kinetic equation
and a Vlasov-like equation within a general framework: It describes the
evolution of the spectrum of a random field that exhibits a
quasi-stationary statistics in the presence of a noninstantaneous
nonlinear response. The kinetic equation sheds new light on the
dynamics of partially coherent nonlinear waves and allows for a
qualitative interpretation of the interplay between the
noninstantaneous nonlinearity and the nonstationary statistics of the
incoherent field. It is shown that the incoherent modulational
instability of a random nonlinear wave can be suppressed by the
noninstantaneous nonlinear response. Moreover, incoherent modulational
instability can prevent the generation of spectral incoherent solitons.
Accepted Fri Feb 5, 2010
White light cavity based on coherent Raman scattering via normal modes of a coupled cavity and atom system
Jiepeng Zhang, Xiaogang Wei, Gessler Hernandez and Yifu Zhu
We describe a white light cavity scheme
based on a cavity quantum electrodynamics system that consists of
multiple three-level atoms confined in an optical cavity and coherently
driven by a free-space, circularly polarized field. A linearly
polarized field is coupled into the cavity mode and its two circular
components induce coherent Raman transitions through the normal modes
of the coupled atom-cavity system. One circular component of the cavity
field experiences anomalous dispersion which enables broadband light
transmission through the cavity. We present the experimental
demonstration of the broadband light transmission through an optical
cavity coupled to cold Rb atoms.
Accepted Fri Feb 5, 2010
Trapping two types of particles using a double ring-shaped radially polarized beam
Yaoju Zhang, Biaofeng Ding and Taikei Suyama
An optical trap method is proposed, which
is based on the illumination of a double-ring-shaped radially polarized
beam (R-TEM sub 11 *). The numerical results based on the vector
diffraction theory show that a highly focused R-TEM sub 11 * beam not
only can produce a bright spot but also can form an optical cage in the
focal region by changing the truncation parameter beta defined as the
ratio of the radius of the aperture to the waist of the beam. The
radiation forces acting on Rayleigh particles are calculated by using
the Rayleigh scattering theory. It is found that the bright spot
generated by the R-TEM sub 11 * beam with a beta value close to 2 can
three-dimensionally trap a particle with a refractive index larger than
that of the ambient. An optical cage or 3D dark spot generated by the
R-TEM sub 11 * beam with a beta value close to 1.3 can
three-dimensionally trap a particle with refractive index smaller than
that of the ambient. Because the adjustment of the truncation parameter
can be actualized by simply changing the radius of a circular aperture
inserted in the front of the lens, only one optical trap system in the
present method can be used to three dimensionally trap two types of
particles with different refractive indices.
Accepted Thu Feb 4, 2010
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