Elina Locane
Wave function and spectral properties of single-particle
emitters
Single-particle emitters are devices that allow for time-controlled on-demand
emission of charged particles, with possible applications in quantum information
processing, nanoelectronics, metrology, and single-electron quantum optics. In
recent years, the progress in fabricating these devices has made it more relevant
than before to investigate their characteristics both experimentally and in theory.
An interesting aspect in quantum transport is that charge flow can be achieved even
without applied bias. Instead, current can be obtained by varying parameters of the
system in such a way that the time-reversal symmetry is broken. Quantum pumps rely
on this regime of operation. In contrast, turnstiles require a bias voltage to obtain
charge transport. Both of these types of devices—quantum pumps and turnstiles—can
be used to attain quantized current, i.e., a one-by-one flow of electrons and/or holes.
A common feature of quantum pumps and turnstiles is that they contain a confinement
with discrete energy levels, in and out of which electrons can tunnel. Controlling the
tunnelling
process
and
understanding its dependence
on the parameters of the
setup is an ongoing challenge.
In particular, it would be
desirable to be able to raise
the number of tunnelling
events per time unit, as well
as to tailor the wave packet of
the emitted particle.
One of the ideas in mind
when
proposing
single- Device containing two single-particle emitters built to
particle emitters was the create indistinguishable electrons in the same quantum
possibility to redefine the unit state (device was reported in Bocquillon et al., Science
of current—the ampere. If we 339, 1054 (2013)). Picture: http://physicsworld.com/
know precisely the number of
electrons and holes that are being emitted per unit time, then the current is also known
provided the value of the elementary charge is defined. Together with the quantum
Hall effect and the Josephson effect, single-particle sources can provide a consistency
test for the fundamental constants e (elementary charge) and h (Planck’s constant).
Among other applications of single-particle emitters is the emerging field of singleelectron quantum optics, the first experiment of which was realized in 2012. Due to
the abovementioned reasons, my master thesis was dedicated to characterize the wave
function and energy spectrum of an electron emitted from such a single-particle
source.
Supervisor: Peter Samuelsson
Thesis 60 ECTS credits in Physics
Physics Deprtment, Lund University
Examensarbete, Naturvetenskap, Lunds universitet