Nano particle trapped between mirrors works as a quantum sensor

Date:
April 7, 2022
Source:
University of Innsbruck
Summary:
Sensors are a pillar of the Internet of Things, providing
the data to control all sorts of objects. Here, precision is
essential, and this is where quantum technologies could make a
difference. Researchers are now demonstrating how nanoparticles
in tiny optical resonators can be transferred into quantum regime
and used as high-precision sensors.



FULL STORY ========================================================================== Sensors are a pillar of the Internet of Things, providing the data to
control all sorts of objects. Here, precision is essential, and this
is where quantum technologies could make a difference. Researchers are
now demonstrating how nanoparticles in tiny optical resonators can be transferred into quantum regime and used as high-precision sensors.


========================================================================== Advances in quantum physics offer new opportunities to significantly
improve the precision of sensors and thus enable new technologies. A
team led by Oriol Romero-Isart of the Institute of Quantum Optics
and Quantum Information at the Austrian Academy of Sciences and the
Department of Theoretical Physics at the University of Innsbruck and a
team lead by Romain Quidant of ETH Zurich are now proposing a new concept
for a high-precision quantum sensor. The researchers suggest that the
motional fluctuations of a nanoparticle trapped in a microscopic optical resonator could be reduced significantly below the zero- point motion,
by exploiting the fast unstable dynamics of the system.

Particle caught between mirrors Mechanical quantum squeezing reduces the uncertainty of motional fluctuations below the zero-point motion, and it
has been experimentally demonstrated in the past with micromechanical resonators in the quantum regime. The researchers now propose a novel
approach, especially tailored to levitated mechanical systems.

"We demonstrate that a properly designed optical cavity can be used to
rapidly and strongly squeeze the motion of a levitated nanoparticle,"
says Katja Kustura of Oriol Romero-Isart's team in Innsbruck. In an
optical resonator, light is reflected between mirrors and it interacts
with the levitated nanoparticle. Such interaction can give rise to
dynamical instabilities, which are often considered undesirable.

The researchers now show how they can instead be used as a
resource. "In the present work, we show how, by properly controlling
these instabilities, the resulting unstable dynamics of a mechanical
oscillator inside an optical cavity leads to mechanical squeezing,"
Kustura says. The new protocol is robust in the presence of dissipation,
making it particularly feasible in levitated optomechanics. In the paper, published in the journal Physical Review Letters, the researchers apply
this approach to a silica nanoparticle coupled to a microcavity via
coherent scattering. "This example shows that we can squeeze the particle
by orders of magnitude below the zero-point motion, even if starting
from an initial thermal state," Oriol Romero-Isart is pleased to say.

The work provides a new use of optical cavities as mechanical quantum squeezers, and it suggests a viable new route in levitated optomechanics
beyond the quantum ground state cooling. Micro-resonators thus offer
an interesting new platform for the design of quantum sensors, which
could be used, for example, in satellite missions, self-driving cars,
and in seismology. The research in Innsbruck and Zurich was financially supported by the European Union.


========================================================================== Story Source: Materials provided by University_of_Innsbruck. Note:
Content may be edited for style and length.


========================================================================== Related Multimedia:
* Nano_particles_trapped_between_mirrors ========================================================================== Journal Reference:
1. Katja Kustura, Carlos Gonzalez-Ballestero, Andre's de los Ri'os
Sommer,
Nadine Meyer, Romain Quidant, Oriol Romero-Isart. Mechanical
Squeezing via Unstable Dynamics in a Microcavity. Physical Review
Letters, 2022; 128 (14) DOI: 10.1103/PhysRevLett.128.143601 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220407141943.htm

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