109 research outputs found
Quantum Teleportation Using Quantum Non-Demolition Technique
We propose a new scheme and protocol for quantum teleportation of a
single-mode field state, based on entanglement produced by quantum
non-demolition interaction. We show that the recently attained results in QND
technique allow to perform the teleportation in quantum regime. We also show
that applying QND coupling to squeezed fields will significantly improve the
quality of teleportation for a given degree of squeezing.Comment: 4 pages RevTeX, 2 figure
Nonlinear coherent loss for generating non-classical states
Here we discuss generation of non-classical states of bosonic mode with the
help of artificially designed loss, namely the nonlinear coherent loss. We show
how to generate superpositions of Fock states, and how it is possible to "comb"
the initial states leaving only states with certain properties in the resulting
superposition (for example, a generation of a superposition of Fock states with
odd number of particles). We discuss purity of generated states and estimate
maximal achievable generation fidelity
Afterpulsing model based on the quasi-continuous distribution of deep levels in single-photon avalanche diodes
We have performed a statistical characterization of the effect of
afterpulsing in a free-running silicon single-photon detector by measuring the
distribution of afterpulse waiting times in response to pulsed illumination and
fitting it by a sum of exponentials. We show that a high degree of goodness of
fit can be obtained for 5 exponentials, but the physical meaning of estimated
characteristic times is dubious. We show that a continuous limit of the sum of
exponentials with a uniform density between the limiting times gives excellent
fitting results in the full range of the detector response function. This means
that in certain detectors the afterpulsing is caused by a continuous band of
deep levels in the active area of the photodetector.Comment: 10 pages, 4 figure
Quantum tight-binding chains with dissipative coupling
We present a one-dimensional tight-binding chain of two-level systems coupled
only through common dissipative Markovian reservoirs. This quantum chain can
demonstrate anomalous thermodynamic behavior contradicting Fourier law.
Population dynamics of individual systems of the chain is polynomial with the
order determined by the initial state of the chain. The chain can simulate
classically hard problems, such as multi-dimensional random walks
Squeezed colour states in gluon jet
The possibility of the formation of squeezed states of gluon fields in quantum chromodynamics due to nonlinear nonperturbative self interaction during jet evolution in the process of e(+)e(-) annihilation into hadrons, which are analogous to the quantum photon squeezed states in quantum electrodynamics, is demonstrated. Additionally, the squeezing parameters are calculated
Measuring photon-photon interactions via photon detection
The strong non-linearity plays a significant role in physics, particularly,
in designing novel quantum sources of light and matter as well as in quantum
chemistry or quantum biology. In simple systems, the photon-photon interaction
can be determined analytically. However, it becomes challenging to obtain it
for more compex systems. Therefore, we show here how to measure strong
non-linearities via allowing the sample to interact with a weakly pumped
quantized leaking optical mode. We found that the detected mean-photon number
versus pump-field frequency shows several peaks. Interestingly, the interval
between neighbour peaks equals the photon-photon interaction potential.
Furthermore, the system exhibits sub-Poissonian photon statistics, entanglement
and photon switching with less than one photon. Finally, we connect our study
with existing related experiments.Comment: 4 pages, 3 figure
About Fundamental Problems of Hydrosphere and Silicate Karst
ΠΠ±ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΌΠΎΠ΄Π΅Π»ΠΈ Π³ΠΈΠ΄ΡΠΎΡΡΠ΅ΡΡ Ρ Π΄Π²ΡΠΌΡ ΠΎΠ±Π»Π°ΡΡΡΠΌΠΈ ΠΏΠΈΡΠ°Π½ΠΈΡ ΠΈ ΡΠ°Π·Π³ΡΡΠ·ΠΊΠΈ ΡΠ°ΡΠΊΡΡΠ²Π°Π΅Ρ Π·Π°ΠΊΠΎΠ½ΠΎΠΌΠ΅ΡΠ½ΠΎΡΡΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΠΎΠ΄Π·Π΅ΠΌΠ½ΡΡ
Π²ΠΎΠ΄, ΠΎΡΡΠ°ΠΆΠ°ΡΡΠΈΠ΅ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΡΠΈΡΡΠ΅ΠΌΡ Π²ΠΎΠ΄Π° β ΠΏΠΎΡΠΎΠ΄Π° β Π³Π°Π·Ρ β ΠΆΠΈΠ²ΠΎΠ΅ Π²Π΅ΡΠ΅ΡΡΠ²ΠΎ ΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅Ρ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ Π³ΠΈΠ΄ΡΠΎΡΡΠ΅ΡΡ Ρ Π΄ΡΡΠ³ΠΈΠΌΠΈ ΠΎΠ±ΠΎΠ»ΠΎΡΠΊΠ°ΠΌΠΈ ΠΠ΅ΠΌΠ»ΠΈ. Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΡ ΠΎΡΠ½ΠΎΠ² ΡΠ½Π΄ΠΎΠ³Π΅Π½Π½ΠΎΠΉ Π³ΠΈΠ΄ΡΠΎΠ³Π΅ΠΎΠ»ΠΎΠ³ΠΈΠΈ Ρ ΠΈΠ·ΡΡΠ΅Π½ΠΈΠ΅ΠΌ ΡΠΈΠ»ΠΈΠΊΠ°ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠΏΠ° ΠΊΠ°ΡΡΡΠ° Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ ΡΠΎΡΡΠ΅Π΄ΠΎΡΠΎΡΠΈΡΡ Π½Π° ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΈ Β«ΡΠ΅ΡΠ½ΡΡ
ΠΈ Π±Π΅Π»ΡΡ
ΠΊΡΡΠΈΠ»ΡΡΠΈΠΊΠΎΠ²Β», ΡΡΡΡΠΊΡΡΡΡ ΠΈ ΠΈΠ·ΠΎΡΠΎΠΏΠ½ΠΎΠ³ΠΎ ΡΠΎΡΡΠ°Π²Π° Π²ΠΎΠ΄ Π² ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΡΠ°Π·ΠΎΠ²ΡΡ
ΡΠΎΡΡΠΎΡΠ½ΠΈΡΡ
, Π½Π° ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠΈ ΡΠΈΡΡΠ°ΡΠΈΠΈ Π² Π·ΠΎΠ½Π΅ Π³ΠΈΠ΄ΡΠΎΠΌΠ΅ΡΠ°Π³Π΅Π½Π΅Π·Π°. ΠΡΠΎ Π±ΡΠ΄Π΅Ρ ΡΠΏΠΎΡΠΎΠ±ΡΡΠ²ΠΎΠ²Π°ΡΡ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π³Π΅ΠΎΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ ΡΠ΅Π»ΠΎΠ²Π΅ΡΠ΅ΡΡΠ²Π° ΠΌΠΈΠ½Π΅ΡΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΈ ΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ΅ΡΡΡΡΠ°ΠΌΠΈ Π½Π° ΠΏΠ΅ΡΡΠΏΠ΅ΠΊΡΠΈΠ²Ρ.Rationale of hydrosphere model with two regions of supply and discharge reveals regularities of ground water formation reflecting the special features of system water β rock β gas β living material and character of interaction of hydrosphere with the other spheres of the Earth. It is necessary to concentrate the development of endogenous hy-drogeology fundamentals with the study of silicate karst on investigation of βwhite and black smokersβ, the structure and isotope composition of water in different phase condi-tions, and on modeling of situation in hydrometagenese zone. It will support the development of geotechnology and providing the humanity with mineral and energetic resources in future
Photon and phonon statistics in a qubit-plasmon-phonon ultrastrong coupling system
We study photon/phonon statistics of a qubit-plasmon-phonon hybrid system in
the ultrastrong coupling regime. The introduced qubit coupling causes parity
conserving and non-conserving situations. We employ an analytic approximation
approach for the parity conserving case to reveal the statistical behaviors of
photons and phonons. It indicates that both photons and phonons show strong
antibunching at the same frequency. Even though the bunching properties of
photons/phonons occupy the dominant regions of the considered frequencies,
phonons tend to weakly antibunching within the photonic strong-bunching area.
In contrast, one can find that the configurations of correlation functions for
both photons and phonons in the parity conserving case are squeezed towards the
central frequency by parity breaking, which directly triggers the reverse
statistical behaviors for the different parties at the low-frequency regions
and the strong bunching properties at other frequency regions. The
photon-phonon cross-correlation function also demonstrates similar
parity-induced differences, indicating that the non-conserving parity induces
the photon-phonon bunching behavior. We finally analyze the delayed
second-order correlation function with different driving frequencies, which
illustrates striking oscillations revealing the occurrence of simultaneous
multiple excitations.Comment: 9 pages, 7 figures. To appear in PR
Optimal dimensionality for quantum cryptography
We perform a comparison of two protocols for generating a cryptographic key
composed from d-valued symbols: one exploiting a string of independent qubits
and another one utilizing d-level systems prepared in states belonging to d+1
mutually unbiased bases. We show that the protocol based on qubits is optimal
for quantum cryptography, since it provides higher security and higher key
generation rate.Comment: Revtex, 4 pages, 1 eps figur
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