281 research outputs found
Can quantum regression theorem be reconciled with quantum fluctuation dissipation theorem ?
In the attempt to derive the regression theorem from the fluctuation
dissipation theorem several authors claim the violation of the former theorem
in the quantum case. Here we pose the question: does it exists a quantum
fluctuation dissipation theorem (QFDT) in its conventional interpretation? It
is shown that the relation usually called as the QFDT is the condition of
detailed macroscopic energetic balance. Following this interpretation the
existing conflict between the two theorems in the quantum case is removed.Comment: 13 pages, 3rd Int. Conf. on Unsolved Problems on Noise (will be
published in Proceedings
12/13/1993 - Initiated Into Phi Alpha Eta Jurges Studzinski.pdf
International audienc
Voltage controlled terahertz transmission through GaN quantum wells
We report measurements of radiation transmission in the 0.220--0.325 THz
frequency domain through GaN quantum wells grown on sapphire substrates at room
and low temperatures. A significant enhancement of the transmitted beam
intensity with the applied voltage on the devices under test is found. For a
deeper understanding of the physical phenomena involved, these results are
compared with a phenomenological theory of light transmission under electric
bias relating the transmission enhancement to changes in the differential
mobility of the two-dimensional electron gas
06/11/1993 - Guernsey Nominated.pdf
International audienc
03/17/1993 - Student Senator At EIU Michelle Gaddini.pdf
International audienc
Unipolar transport and shot noise in metal-semiconductor-metal structures
We carry out a self-consistent analytical theory of unipolar current and
noise properties of metal-semiconductor-metal structures made of highly
resistive semiconductors in the presence of an applied bias of arbitrary
strength. By including the effects of the diffusion current we succeed to study
the whole range of carrier injection conditions going from low level injection,
where the structure behaves as a linear resistor, to high level injection,
where the structure behaves as a space charge limited diode. We show that these
structures display shot noise at the highest voltages. Remarkably the crossover
from Nyquist noise to shot noise exhibits a complicate behavior with increasing
current where an initial square root dependence (double thermal noise) is
followed by a cubic power law.Comment: 10 pages, 8 figures. Accepted for publication in Journal of Applied
Physics (Scheduled 1 January 2003
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