Speaker
Prof.
Benjamin Huard
(Ecole Normale Supérieure)
Description
Quantum thermodynamics of information addresses the link
between information and energy in the quantum regime.
Entanglement and measurement backaction are known to deeply
affect information processing and their impact on quantum
thermodynamics has attracted a lot of theoretical activity.
A basic illustration of these ideas consists in devising a
quantum version of the Maxwell demon that uses information
on a system to extract work from it.
In this talk, we will discuss an elementary thermal machine
able to extract work from a superconducting quantum bit from
the knowledge it acquires. We have realized such a machine
using superconducting circuits in two manners. First, by
measurement based feedback, a macroscopic observer acquires
information about the quantum system and reacts on it.
Second, using a microwave mode as a quantum Maxwell demon,
we are able to directly measure the extracted work from a
thermalized qubit. We track quantitatively the flows of
energy and entropy at any step of the process owing to the
high level of controllability of superconducting circuits.
When the qubit starts in a coherent superposition, this work
gives a direct picture of the power flows out of a qubit
during coherent evolution and a measurement.
Primary author
Prof.
Benjamin Huard
(Ecole Normale Supérieure)
