Measurement-assisted quantum communication in spin channels with dephasing

Spin dephasing in quantum wires

We study high-field spin transport in a quantum wire using a semiclassical approach. Spin dephasing (or spin depolarization) in the wire is caused by D’yakonov-Perel’ relaxation associated with bulk inversion asymmetry (Dresselhaus spin-orbit coupling) and structural inversion asymmetry (Rashba spin-orbit coupling). The depolarization rate is found to depend strongly on the initial polarization...

Quantum capacity of dephasing channels with memory

We show that the amount of coherent quantum information that can be reliably transmitted down a dephasing channel with memory is maximized by separable input states. In particular, we model the channel as a Markov chain or a multimode environment of oscillators. While in the first model the maximization is achieved for the maximally mixed input state, in the latter it is convenient to exploit t...

Dephasing-assisted transport: quantum networks and biomolecules

Transport phenomena are fundamental in physics. They allow for information and energy to be exchanged between individual constituents of communication systems, networks or even biological entities. Environmental noise will generally hinder the efficiency of the transport process. However, and contrary to intuition, there are situations in classical systems where thermal fluctuations are actuall...

Quantum Transport with Spin Dephasing: A Nonequilibrium Green's Function Approach

A quantum transport model incorporating spin scattering processes is presented using the non-equilibrium Green's function (NEGF) formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with...

Quantum transport with spin dephasing: A nonequlibrium Green's function approach