15,913 research outputs found
A study of thermal response of the lunar surface at the landing site during the descent of the Lunar Excursion Module /LEM/
Thermal response of lunar surface at landing site due to radiative and convective heat transfer from LEM exhaust nozzl
Entangled-state cryptographic protocol that remains secure even if nonlocal hidden variables exist and can be measured with arbitrary precision
Standard quantum cryptographic protocols are not secure if one assumes that
nonlocal hidden variables exist and can be measured with arbitrary precision.
The security can be restored if one of the communicating parties randomly
switches between two standard protocols.Comment: Shortened version, accepted in Phys. Rev.
Unraveling quantum dissipation in the frequency domain
We present a quantum Monte Carlo method for solving the evolution of an open
quantum system. In our approach, the density operator evolution is unraveled in
the frequency domain. Significant advantages of this approach arise when the
frequency of each dissipative event conveys information about the state of the
system.Comment: 4 pages, 4 Postscript figures, uses RevTe
Monetary policy and economic activity: a postwar review
Monetary policy ; Financial markets ; Economic conditions
50 nm GaAs mHEMTs and MMICs for ultra-low power distributed sensor network applications
We report well-scaled 50 nm GaAs metamorphic HEMTs (mHEMTs) with DC power consumption in the range
1-150 ΜW/Μ demonstrating f<sub>T</sub> of 30-400 GHz. These metrics enable the realisation of ultra-low power (<500
ΜW) radio transceivers for autonomous distributed sensor network applications
Sympathetic cooling of trapped fermions by bosons in the presence of particle losses
We study the sympathetic cooling of a trapped Fermi gas interacting with an
ideal Bose gas below the critical temperature of the Bose-Einstein
condensation. We derive the quantum master equation, which describes the
dynamics of the fermionic component, and postulating the thermal distribution
for both gases we calculate analytically the rate at which fermions are cooled
by the bosonic atoms. The particle losses constitute an important source of
heating of the degenerate Fermi gas. We evaluate the rate of loss-induced
heating and derive analytical results for the final temperature of fermions,
which is limited in the presence of particle losses.Comment: 7 pages, 2 figures, EPL style; final versio
Kinetics of Bose-Einstein Condensation in a Trap
The formation process of a Bose-Einstein condensate in a trap is described
using a master equation based on quantum kinetic theory, which can be well
approximated by a description using only the condensate mode in interaction
with a thermalized bath of noncondensate atoms. A rate equation of the form n =
2W(n)[(1-exp((mu_n - mu)/kT))n + 1] is derived, in which the difference between
the condensate chemical potential mu_n and the bath chemical potential mu gives
the essential behavior. Solutions of this equation, in conjunction with the
theoretical description of the process of evaporative cooling, give a
characteristic latency period for condensate formation and appear to be
consistent with the observed behavior of both rubidium and sodium condensate
formation.Comment: 9 pages, Revte
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