3,795 research outputs found
Dissipative tunneling through a parabolic potential in the Lindblad theory of open quantum systems
By using the Lindblad theory for open quantum systems, an analytical
expression of the tunneling probability through an inverted parabola is
obtained. This penetration probability depends on the environment coefficients.
It is shown that the tunneling probability increases with the dissipation and
the temperature of the thermal bath.Comment: 16 pages, 6 figure
Phase Space Representation for Open Quantum Systems within the Lindblad Theory
The Lindblad master equation for an open quantum system with a Hamiltonian
containing an arbitrary potential is written as an equation for the Wigner
distribution function in the phase space representation. The time derivative of
this function is given by a sum of three parts: the classical one, the quantum
corrections and the contribution due to the opening of the system. In the
particular case of a harmonic oscillator, quantum corrections do not exist.Comment: 19 pages, Latex, accepted for publication in Int. J. Mod. Phys.
Triple resonant four-wavemixing boosts the yield of continuous coherent VUV generation
Continuous-wave coherent radiation in the vacuum ultraviolet (VUV)wavelength
region at 121 nm will be essential for future laser-cooling of trapped
antihydrogen [1]. Cold antihydrogen will enable both tests of the fundamental
symmetry between matter and antimatter at unprecedented experimental precision
[2] and also experiments in antimatter gravity [3]. Another fascinating
application of narrowband continuous laser radiation in the VUV is quantum
information processing using single trapped ions in Rydberg-states [4, 5]. Here
we describe highly efficient continuous four-wave mixing in the VUV by using
three different fundamental wavelengths with a sophisticated choice of
detunings to resonances of the nonlinear medium. Up to 6 microwatts of vacuum
ultraviolet radiation at 121 nm can be generated which corresponds to an
increase of three orders of magnitude in efficiency.Comment: 11 pages, 3 figure
Continuous Lyman-alpha generation by four-wave mixing in mercury for laser-cooling of antihydrogen
Cooling antihydrogen atoms is important for future experiments both to test
the fundamental CPT symmetry by high-resolution laser spectroscopy and also to
measure the gravitational acceleration of antimatter. Laser-cooling of
antihydrogen can be done on the strong 1S-2P transition at the wavelength of
Lyman-alpha (121.6nm). A continuous-wave laser at the Lyman-alpha wavelength
based on solid-state fundamental lasers is described. By using a two-photon and
a near one photon resonance a scan across the whole phasematching curve of the
four-wave mixing process is possible. Furthermore the influence of the beam
profile of one fundamental beam on the four-wave mixing process is studied.Comment: 4 pages, 4 figure
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