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: A quantum logic gate between light and matter

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

CERN: World-record current in a superconductor

16 hours ago

In the framework of the High-Luminosity LHC project, experts from the CERN Superconductors team recently obtained a world-record current of 20 kA at 24 K in an electrical transmission line consisting of two ...

High power laser sources at exotic wavelengths

Apr 14, 2014

High power laser sources at exotic wavelengths may be a step closer as researchers in China report a fibre optic parametric oscillator with record breaking efficiency. The research team believe this could ...

Novel technique opens door to better solar cells

Apr 14, 2014

A team of scientists, led by Assistant Professor Andrivo Rusydi from the Department of Physics at the National University of Singapore's (NUS) Faculty of Science, has successfully developed a technique to ...

User comments : 0

More news stories

CERN: World-record current in a superconductor

In the framework of the High-Luminosity LHC project, experts from the CERN Superconductors team recently obtained a world-record current of 20 kA at 24 K in an electrical transmission line consisting of two ...

Glasses strong as steel: A fast way to find the best

Scientists at Yale University have devised a dramatically faster way of identifying and characterizing complex alloys known as bulk metallic glasses (BMGs), a versatile type of pliable glass that's stronger than steel.

Low Vitamin D may not be a culprit in menopause symptoms

A new study from the Women's Health Initiative (WHI) shows no significant connection between vitamin D levels and menopause symptoms. The study was published online today in Menopause, the journal of The North American Menopa ...

Astronomers: 'Tilt-a-worlds' could harbor life

A fluctuating tilt in a planet's orbit does not preclude the possibility of life, according to new research by astronomers at the University of Washington, Utah's Weber State University and NASA. In fact, ...