1,374 research outputs found
Conditional generation of an arbitrary superposition of coherent states
We present a scheme to conditionally generate an arbitrary superposition of a
pair of coherent states from a squeezed vacuum by means of the modified photon
subtraction where a coherent state ancilla and two on/off type detectors are
used. We show that, even including realistic imperfections of the detectors,
our scheme can generate a target state with a high fidelity. The amplitude of
the generated states can be amplified by conditional homodyne detections.Comment: 7 pages, 5 figure
Temporally multiplexed superposition states of continuous variables
We study non-Gaussian states generated by two-photon subtraction from a cw
squeezed light source. In a cw scheme one can subtract two photons from the
source with a designated time separation and can genarate temporally
multiplexed superposition states of continuous variables. We numerically study
the properties of these states in the light of bosonic interference in the time
domain. In an appropriate temporal mode amplified kittens are produced in a
region where the time separation is comparable with the correlation time of
squeezed packets.Comment: 12 pages, 10 figure
Large amplitude coherent state superposition generated by a time-separated two-photon subtraction from a continuous wave squeezed vacuum
Theoretical analysis is given for a two-photon subtraction from a continuous
wave (CW) squeezed vacuum with finite time separation between two detection
events. In the CW photon subtraction process, the generated states are
inevitably described by temporal mutimode states. Our approach is based on
Schr\"{o}dinger picture which provides mathematically simple forms and an
intuitive understanding of its multimode structure. We show that, in our
process, the photon subtracted squeezed vacuum is generated in two temporal
modes and one of these modes acts as an ancillary mode to make the other one a
large amplitude coherent state superposition.Comment: 9 pages, 8 figure
Effective squeezing enhancement via measurement-induced non-Gaussian operation and its application to dense coding scheme
We study the measurement-induced non-Gaussian operation on the single- and
two-mode \textit{Gaussian} squeezed vacuum states with beam splitters and
on-off type photon detectors, with which \textit{mixed non-Gaussian} states are
generally obtained in the conditional process. It is known that the
entanglement can be enhanced via this non-Gaussian operation on the two-mode
squeezed vacuum state. We show that, in the range of practical squeezing
parameters, the conditional outputs are still close to Gaussian states, but
their second order variances of quantum fluctuations and correlations are
effectively suppressed and enhanced, respectively. To investigate an
operational meaning of these states, especially entangled states, we also
evaluate the quantum dense coding scheme from the viewpoint of the mutual
information, and we show that non-Gaussian entangled state can be advantageous
compared with the original two-mode squeezed state.Comment: REVTeX4, 14 pages with 21 figure
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