Articles you may be interested inFinite-frequency current (shot) noise in coherent resonant tunneling through a coupled-quantum-dot interferometer J. Appl. Phys. Tunneling resonances and Andreev reflection through an interaction quantum dot coupled with two half metals and a superconductor J. Appl. Phys. 99, 08F713 (2006); 10.1063/1.2173625 Theoretical investigations for shot noise in correlated resonant tunneling through a quantum coupled system J. Appl. Phys. 99, 063710 (2006); 10.1063/1.2183352 Transition from sub-Poissonian to super-Poissonian shot noise in planar cold cathodes

We derive the quantum rate equations for an Aharonov-Bohm interferometer with two vertically coupled quantum dots embedded in each of two arms by means of the nonequilibrium Green's function in the sequential tunneling regime. Basing on these equations, we investigate time-dependent resonant tunneling under a small amplitude irradiation and find that the resonant photon-assisted tunneling peaks in photocurrent demonstrate a combination behavior of Fano and Lorentzian resonances due to the interference effect between the two pathways in this parallel configuration, which is controllable by threading the magnetic flux inside this device.

In this paper, we carry out a theoretical analysis of the zero-frequency and finite-frequency shot noise in electron tunneling through a two-level interacting system connected to two leads, when a coherent coupling between the two levels is present, by means of recently developed bias-voltage and temperature dependent quantum rate equations. For this purpose, we generalize the traditional generation-recombination approach for shot noise of two-terminal tunneling devices properly to take into account the coherent superposition of different electronic states (quantum effects). As applications, analytical and numerical investigations have been given in detail for two cases: (1) electron tunneling through a quantum dot connected to ferromagnetic leads with intradot spin-flip scattering, and (2) spinless fermions tunneling through seriesly coupled quantum dots, focusing on the shot noise as functions of bias-voltage and frequency.

Fatal reactions related to subcutaneous allergen immunotherapy are rare: one event in 2.5 million injections has been reported in the USA and none in Europe. The prevalence of very severe systemic reactions (systemic adverse events [SAEs]) is one in 1 million injections. Though the serious events rate is decreasing and the majority of SAEs (∼0.2% per injection) are moderate and reversible, they still represent a major concern. Uncontrolled asthma, long-term therapy with β-blockers and high degree of allergen sensitivity are generally considered risk factors. The relevance of other conditions, like previous local reactions, the use of extracts conjugated with adjuvants and accelerated build-up schedules is controversial, as well as the role of preventative strategies. A careful risk assessment of patients and optimal administration procedures may significantly decrease the risk of SAEs. However, more uniform safety data are required and an accurate safety profile should be provided for every allergen product.

We examine the spin current generated by quantum dots embedded in an optical microcavity. The dots are connected to leads, which allow electrons to tunnel into and out of the dot. The spin current is generated by spin flip transitions induced by a quantized electromagnetic field inside the cavity with one of the Zeeman states lying below the Fermi level of the leads and the other above. In the limit of strong Coulomb blockade, this model is analogous to the Jaynes-Cummings model in quantum optics. We find that the cavity field amplitude and the spin current exhibit bistability as a function of the laser amplitude, which is driving the cavity mode. Even in the limit of a single dot, the spin current and the Q-distribution of the cavity field have a bimodal structure.