35,713 research outputs found
Attacking quantum key distribution with single-photon two-qubit quantum logic
The Fuchs-Peres-Brandt (FPB) probe realizes the most powerful individual
attack on Bennett-Brassard 1984 quantum key distribution (BB84 QKD) by means of
a single controlled-NOT (CNOT) gate. This paper describes a complete physical
simulation of the FPB-probe attack on polarization-based BB84 QKD using a
deterministic CNOT constructed from single-photon two-qubit quantum logic.
Adding polarization-preserving quantum nondemolition measurements of photon
number to this configuration converts the physical simulation into a true
deterministic realization of the FPB attack.Comment: 8 pages, 9 figures; references added, 1 new figure, appendix
expanded; accepted for publication in Phys. Rev.
Pion Interferometry for Hydrodynamical Expanding Source with a Finite Baryon Density
We calculate the two-pion correlation function for an expanding hadron source
with a finite baryon density. The space-time evolution of the source is
described by relativistic hydrodynamics and the Hanbury-Brown-Twiss (HBT)
radius is extracted after effects of collective expansion and multiple
scattering on the HBT interferometry have been taken into account, using
quantum probability amplitudes in a path-integral formalism. We find that this
radius is substantially smaller than the HBT radius extracted from the
freeze-out configuration.Comment: 4 pages, 2 figure
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