Nanoscale physics

Perfect absorbing in quantum nanoscale networks
E. Zhitlukhina1, M. Belogolovskii2, P. Seidel3
1 Department of Phase Transitions, Donetsk Institute for Physics and Engineering of the NAS of Ukraine. Prospect Nauki, 46, Kyiv-03028, Ukraine.
E-mail: elena_zhitlukhina@ukr.net
2 Faculty of Physics and Technology, Donetsk National University, 600-richchia Str., 21, 21021 Vinnytsia-21021, Ukraine. 
3 Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Helmholtzweg, 5, Jena-07743, Germany. 

Coherent perfect absorption (CPA) is a general and robust phenomenon based on the interference of mutually coherent waves able to create a forward-directed plane wave cancelling the incident plane wave and, at the same time, provide no radiation in the direction towards the source. A very important property of CPAs, which follows from the analytic properties of the related scattering matrix, is that we can change the output intensity simply by changing the relative phase of the input beams. Its effectiveness has been recently shown for a two-channel CPA device, which absorbs the output of two lasers whose beams have appropriate phases and amplitudes. 
In this work, we show that a similar phenomenon can be realized in a three-terminal nanoscale metallic setup formed by a charge emitter and two drain wires (one of them incudes a metallic inset). Although coherent interference effects in such device are similar to those in optical counterparts, hybrid solid-state devices are more flexible and potentially useable as transducers, modulators, or switches in nanoelectronic circuits. The advantage is achieved by inserting a superconducting inset in another outgoing wire and originates from the energy dependence of scattering wave amplitudes for energies comparable with the superconducting gap value. This feature permits self-controllable transferring  quantum information encoded in a wave packet that is injected by on-demand mesoscopic electron sources based on trains of levitons. The latter excitations are created by a properly designed Lorentzian voltage pulse with a half-width . Our numerical simulations of the coherent charge transport in a three-arm nanodevice shows that operation and performance of the Y-shaped splitter could be effectively governed by changing the characteristic time .
This work has been supported by the joint German-Ukrainian project “Controllable quantum-information transfer in superconducting networks” (DFG project number SE 664/21). M. Belogolovskii is thankful to the Fundamental Research Programme funded by the MES of Ukraine (Project No. 0117U002360).