3,415 research outputs found
Symmetry and inert states of spin Bose Condensates
We construct the list of all possible inert states of spin Bose condensates
for . In doing so, we also obtain their symmetry properties. These
results are applied to classify line defects of these spin condensates at zero
magnetic field.Comment: an error in Sec III C correcte
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Multinational Learning under Asymmetric Information
The aim of this paper is to analyze the competition between a multinational and the incumbent firm in a foreign market under asymmetric information about demand and unobservable outputs. It is shown that the incumbent firm increases its production in the first period to signal to the multinational that the demand is low. The multinational reduces its output in the foreign market in order to signal-jam. In addition, the multinational increases its production in the other market. However, total production of the multinational is lower. Implications for research and development expenditure by the multinational are examined
Teleportation of a quantum state of a spatial mode with a single massive particle
Mode entanglement exists naturally between regions of space in ultra-cold
atomic gases. It has, however, been debated whether this type of entanglement
is useful for quantum protocols. This is due to a particle number
superselection rule that restricts the operations that can be performed on the
modes. In this paper, we show how to exploit the mode entanglement of just a
single particle for the teleportation of an unknown quantum state of a spatial
mode. We detail how to overcome the superselection rule to create any initial
quantum state and how to perform Bell state analysis on two of the modes. We
show that two of the four Bell states can always be reliably distinguished,
while the other two have to be grouped together due to an unsatisfied phase
matching condition. The teleportation of an unknown state of a quantum mode
thus only succeeds half of the time.Comment: 12 pages, 1 figure, this paper was presented at TQC 2010 and extends
the work of Phys. Rev. Lett. 103, 200502 (2009
Quantum Theory and Time Asymmetry
The relation between quantum measurement and thermodynamically irreversible
processes is investigated. The reduction of the state vector is fundamentally
asymmetric in time and shows an observer-relatedness which may explain the
double interpretation of the state vector as a representation of physical
states as well as of information about them. The concept of relevance being
used in all statistical theories of irreversible thermodynamics is shown to be
based on the same observer-relatedness. Quantum theories of irreversible
processes implicitly use an objectivized process of state vector reduction. The
conditions for the reduction are discussed, and I speculate that the final
(subjective) observer system might even be carried by a spacetime point.Comment: Latex version of a paper published in 1979 (with minor revisions), 18
page
The Pauli Equation for Probability Distributions
The "marginal" distributions for measurable coordinate and spin projection is
introduced. Then, the analog of the Pauli equation for spin-1/2 particle is
obtained for such probability distributions instead of the usual wave
functions. That allows a classical-like approach to quantum mechanics. Some
illuminating examples are presented.Comment: 14 pages, ReVTe
Left and right handedness of fermions and bosons
It is shown, by using Grassmann space to describe the internal degrees of
freedom of fermions and bosons, that the Weyl like equation exists not only for
massless fermions but also for massless gauge bosons. The corresponding states
have well defined helicity and handedness. It is shown that spinors and gauge
bosons of the same handedness only interact.Comment: 18 pages, LaTeX, no figures, typographical errors corrected and a few
sentences added to clarify some issue
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