Quantum interference in mesoscopics

P. Singha Deo, A. M. Jayannavar

A. P. Alodjants, Alexei V. Prokhorov, A. Yu. Leksin +1 more

The problem of formation of macroscopic (mesoscopic) coherent superposition of polarization states for boson-like systems are discussed for the first time. The quantum interference of two (and/or more) coherent states in boson systems results in nonclassical polarization states being described by us by different way: the Wigner quasi- distribution function, boson statistics and entropy of quantum states. The phase transition from classical to quantum state of the system in such a `frozen' mesoscopic system (quantum dots) is obtained. The behavior of the Wigner function under the phase transitino demonstrates the fractal-like structure. The application of considered coherent superposition of quantum states and induced phase transition in mesoscopic systems to construction of the quantum logical gates for quantum computation are discussed as well.

Nicola Lo Gullo

Juan Diego Urbina, Jack Kuipers, Quirin Hummel +1 more

We consider the many-body scattering of non-interacting identical particles in mesoscopic chaotic cavities. A complete enumeration of all interfering paths allows us to discriminate single-particle effects from many-body interference due to quantum indistinguishability. In the thermodynamic limit of large particle number massive quantum interference results in a macroscopic, coherent manifestation of many-body correlations. We also incorporate mesoscopic dephasing, present even when the particles scatter simultaneously. Under further simplifications characteristic for optical scenarios, our methods can be used to address open issues related to the Boson Sampling problem.

Jian‐Bai Xia

A one-dimensional quantum waveguide theory for mesoscopic structures is proposed, and the boundary conditions of the wave functions at an intersection are given. The Aharonov-Bohm effect is quantitatively discussed with use of this theory, and the reflection, transmission amplitudes, etc., are given as functions of the magnetic flux, the arm lengths, and the wave vector. It is found that the oscillating current consists of a significant component of the second harmonic. This theory is also applied to investigate quantum-interference devices. The results on the Aharonov-Bohm effect and the quantum-interference devices are found to be in agreement with previous theoretical results.

B. Krämer