6,240 research outputs found
Storage and Retrieval of Thermal Light in Warm Atomic Vapor
We report slowed propagation and storage and retrieval of thermal light in
warm rubidium vapor using the effect of electromagnetically-induced
transparency (EIT). We first demonstrate slowed-propagation of the probe
thermal light beam through an EIT medium by measuring the second-order
correlation function of the light field using the Hanbury-BrownTwiss
interferometer. We also report an experimental study on the effect of the EIT
slow-light medium on the temporal coherence of thermal light. Finally, we
demonstrate the storage and retrieval of thermal light beam in the EIT medium.
The direct measurement of the photon number statistics of the retrieved light
field shows that the photon number statistics is preserved during the storage
and retrieval process.Comment: 4 pages, 4 figure
Reversing the Weak Quantum Measurement for a Photonic Qubit
We demonstrate the conditional reversal of a weak (partial-collapse) quantum
measurement on a photonic qubit. The weak quantum measurement causes a
nonunitary transformation of a qubit which is subsequently reversed to the
original state after a successful reversing operation. Both the weak
measurement and the reversal operation are implemented linear optically. The
state recovery fidelity, determined by quantum process tomography, is shown to
be over 94% for partial-collapse strength up to 0.9. We also experimentally
study information gain due to the weak measurement and discuss the role of the
reversing operation as an information erasure
Experimental verification of the commutation relation for Pauli spin operators using single-photon quantum interference
We report experimental verification of the commutation relation for Pauli
spin operators using quantum interference of the single-photon polarization
state. By superposing the quantum operations and on a single-photon polarization state, we have experimentally
implemented the commutator, , and the anticommutator,
, and have demonstrated the relative phase factor
of between and operations. The
experimental quantum operation corresponding to the commutator, , showed process fidelity of 0.94 compared to the ideal
operation and is determined to be .Comment: 4pages, 3 figure
South Koreans' attitudes toward foreigners, minorities and multiculturalism
노트 : Paper prepared for presentation at the annual meeting of the American Sociological Association, Boston, MA from August 1-4, 2008
Realizing Physical Approximation of the Partial Transpose
The partial transpose by which a subsystem's quantum state is solely
transposed is of unique importance in quantum information processing from both
fundamental and practical point of view. In this work, we present a practical
scheme to realize a physical approximation to the partial transpose using local
measurements on individual quantum systems and classical communication. We then
report its linear optical realization and show that the scheme works with no
dependence on local basis of given quantum states. A proof-of-principle
demonstration of entanglement detection using the physical approximation of the
partial transpose is also reported.Comment: 5 pages with appendix, 3 figure
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