Quantum information motion control is now improved

Apr 03, 2012

Physicists have recently devised a new method for handling the effect of the interplay between vibrations and electrons on electronic transport. Their paper is about to be published in the European Physical Journal B. This study, led by scientists from Zhejiang University, Hangzhou, China, and the Centre for Computational Science and Engineering at the National University of Singapore, could have implications for quantum computers due to improvements in the transport of discrete amounts of information, known as qubits, that are encoded in electrons.

The authors created an model to assess electrons' current fluctuations when they are subjected to quantized modes of vibration, also known as . In the model, phonons are induced by a nanomechanical resonator. To better monitor electron transport, it is coupled to a system that was chosen for its ability to confine one or several electrons, called double quantum dot (DQD). Unlike previous studies, this work imposed arbitrary strong coupling regimes between electrons in the DQD and the phonons produced by the resonator.

The authors successfully controlled the excitations of the phonons without impacting the transport of . To do so, they decoupled the electron-phonon interaction by the so-called coherent phonon states method, which is based on reaching resonance modes of phonons. They have shown that when the energy excess between the two of the DQD system is sufficient to create an integer number of phonons, electrons can reach resonance and tunnel from one quantum dot to the other. In strong electron-phonon coupling regimes, multi-phonon excitations can thus enhance the electron transport.

As the electron-phonon coupling becomes even stronger, the phenomenon of phonon scattering represses electron transport and confines the electrons. The fluctuations of electron current could therefore be controlled by tuning the electron-phonon coupling, which makes it a good quantum switch to control the transport of information in quantum computers.

Explore further: Quantum teleportation on a chip

More information: Wang C., Ren J., Li B., Chen Q-H. (2012), Quantum transport of double quantum dots coupled to an oscillator in arbitrary strong coupling regime, European Physical Journal B (EPJ B). DOI 10.1140/epjb/e2012-30027-1

Related Stories

Quantum leap for phonon lasers

Feb 22, 2010

Physicists have taken major step forward in the development of practical phonon lasers, which emit sound in much the same way that optical lasers emit light. The development should lead to new, high-resolution ...

Recommended for you

Quantum teleportation on a chip

17 hours ago

The core circuits of quantum teleportation, which generate and detect quantum entanglement, have been successfully integrated into a photonic chip by an international team of scientists from the universities ...

Cooling massive objects to the quantum ground state

18 hours ago

Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. Now researchers have proposed an optomechanically-induced-transparency cooling ...

Scientists succeed in linking two different quantum systems

Mar 30, 2015

Physicists at the Universities of Bonn and Cambridge have succeeded in linking two completely different quantum systems to one another. In doing so, they have taken an important step forward on the way to a quantum computer. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.