1,381 research outputs found
Parametric coupling between macroscopic quantum resonators
Time-dependent linear coupling between macroscopic quantum resonator modes
generates both a parametric amplification also known as a {}"squeezing
operation" and a beam splitter operation, analogous to quantum optical systems.
These operations, when applied properly, can robustly generate entanglement and
squeezing for the quantum resonator modes. Here, we present such coupling
schemes between a nanomechanical resonator and a superconducting electrical
resonator using applied microwave voltages as well as between two
superconducting lumped-element electrical resonators using a r.f.
SQUID-mediated tunable coupler. By calculating the logarithmic negativity of
the partially transposed density matrix, we quantitatively study the
entanglement generated at finite temperatures. We also show that
characterization of the nanomechanical resonator state after the quantum
operations can be achieved by detecting the electrical resonator only. Thus,
one of the electrical resonator modes can act as a probe to measure the
entanglement of the coupled systems and the degree of squeezing for the other
resonator mode.Comment: 15 pages, 4 figures, submitte
Tunable phonon blockade in weakly nonlinear coupled mechanical resonators via Coulomb interaction
Realizing quantum mechanical behavior in micro- and nanomechanical resonators
has attracted continuous research effort. One of the ways for observing quantum
nature of mechanical objects is via the mechanism of phonon blockade. Here, we
show that phonon blockade could be achieved in a system of two weakly nonlinear
mechanical resonators coupled by a Coulomb interaction. The optimal blockade
arises as a result of the destructive quantum interference between paths
leading to two-phonon excitation. It is observed that, in comparison to a
single drive applied on one mechanical resonator, driving both the resonators
can be beneficial in many aspects; such as, in terms of the temperature
sensitivity of phonon blockade and also with regard to the tunability, by
controlling the amplitude and the phase of the second drive externally. We also
show that via a radiation pressure induced coupling in an optomechanical
cavity, phonon correlations can be measured indirectly in terms of photon
correlations of the cavity mode
Diamond Integrated Optomechanical Circuits
Diamond offers unique material advantages for the realization of micro- and
nanomechanical resonators due to its high Young's modulus, compatibility with
harsh environments and superior thermal properties. At the same time, the wide
electronic bandgap of 5.45eV makes diamond a suitable material for integrated
optics because of broadband transparency and the absence of free-carrier
absorption commonly encountered in silicon photonics. Here we take advantage of
both to engineer full-scale optomechanical circuits in diamond thin films. We
show that polycrystalline diamond films fabricated by chemical vapour
deposition provide a convenient waferscale substrate for the realization of
high quality nanophotonic devices. Using free-standing nanomechanical
resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate
efficient optomechanical transduction via gradient optical forces. Fabricated
diamond resonators reproducibly show high mechanical quality factors up to
11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for
all-optical sensing and optomechanical signal processing at ultra-high
frequencies
Diamond electro-optomechanical resonators integrated in nanophotonic circuits
Diamond integrated photonic devices are promising candidates for emerging
applications in nanophotonics and quantum optics. Here we demonstrate active
modulation of diamond nanophotonic circuits by exploiting mechanical degrees of
freedom in free-standing diamond electro-optomechanical resonators. We obtain
high quality factors up to 9600, allowing us to read out the driven
nanomechanical response with integrated optical interferometers with high
sensitivity. We are able to excite higher order mechanical modes up to 115 MHz
and observe the nanomechanical response also under ambient conditions.Comment: 15 pages, 4 figure
Optomechanical measurement of thermal transport in two-dimensional MoSe2 lattices
Nanomechanical resonators have emerged as sensors with exceptional
sensitivities. These sensing capabilities open new possibilities in the studies
of the thermodynamic properties in condensed matter. Here, we use mechanical
sensing as a novel approach to measure the thermal properties of
low-dimensional materials. We measure the temperature dependence of both the
thermal conductivity and the specific heat capacity of a transition metal
dichalcogenide (TMD) monolayer down to cryogenic temperature, something that
has not been achieved thus far with a single nanoscale object. These
measurements show how heat is transported by phonons in two-dimensional
systems. Both the thermal conductivity and the specific heat capacity
measurements are consistent with predictions based on first-principles
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