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

Evaluating the Impedance Field through several transport models: a comparison

J. APPL. PHYS

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