71 research outputs found
Stationary Entangled Radiation from Micromechanical Motion
Mechanical systems facilitate the development of a new generation of hybrid
quantum technology comprising electrical, optical, atomic and acoustic degrees
of freedom. Entanglement is the essential resource that defines this new
paradigm of quantum enabled devices. Continuous variable (CV) entangled fields,
known as Einstein-Podolsky-Rosen (EPR) states, are spatially separated two-mode
squeezed states that can be used to implement quantum teleportation and quantum
communication. In the optical domain, EPR states are typically generated using
nondegenerate optical amplifiers and at microwave frequencies Josephson
circuits can serve as a nonlinear medium. It is an outstanding goal to
deterministically generate and distribute entangled states with a mechanical
oscillator. Here we observe stationary emission of path-entangled microwave
radiation from a parametrically driven 30 micrometer long silicon nanostring
oscillator, squeezing the joint field operators of two thermal modes by
3.40(37) dB below the vacuum level. This mechanical system correlates up to 50
photons/s/Hz giving rise to a quantum discord that is robust with respect to
microwave noise. Such generalized quantum correlations of separable states are
important for quantum enhanced detection and provide direct evidence for the
non-classical nature of the mechanical oscillator without directly measuring
its state. This noninvasive measurement scheme allows to infer information
about otherwise inaccessible objects with potential implications in sensing,
open system dynamics and fundamental tests of quantum gravity. In the near
future, similar on-chip devices can be used to entangle subsystems on vastly
different energy scales such as microwave and optical photons.Comment: 13 pages, 5 figure
Mechanical On-Chip Microwave Circulator
Nonreciprocal circuit elements form an integral part of modern measurement
and communication systems. Mathematically they require breaking of
time-reversal symmetry, typically achieved using magnetic materials and more
recently using the quantum Hall effect, parametric permittivity modulation or
Josephson nonlinearities. Here, we demonstrate an on-chip magnetic-free
circulator based on reservoir engineered optomechanical interactions.
Directional circulation is achieved with controlled phase-sensitive
interference of six distinct electro-mechanical signal conversion paths. The
presented circulator is compact, its silicon-on-insulator platform is
compatible with both superconducting qubits and silicon photonics, and its
noise performance is close to the quantum limit. With a high dynamic range, a
tunable bandwidth of up to 30 MHz and an in-situ reconfigurability as beam
splitter or wavelength converter, it could pave the way for superconducting
qubit processors with integrated and multiplexed on-chip signal processing and
readout.Comment: References have been update
Tunable mechanical coupling between driven microelectromechanical resonators
We present a microelectromechanical system, in which a silicon beam is
attached to a comb-drive actuator, that is used to tune the tension in the
silicon beam, and thus its resonance frequency. By measuring the resonance
frequencies of the system, we show that the comb-drive actuator and the silicon
beam behave as two strongly coupled resonators. Interestingly, the effective
coupling rate (~ 1.5 MHz) is tunable with the comb-drive actuator (+10%) as
well as with a side-gate (-10%) placed close to the silicon beam. In contrast,
the effective spring constant of the system is insensitive to either of them
and changes only by 0.5%. Finally, we show that the comb-drive actuator
can be used to switch between different coupling rates with a frequency of at
least 10 kHz.Comment: 5 pages, 4 figures, 1 tabl
Optomechanics for quantum technologies
The ability to control the motion of mechanical systems through interaction with light has opened the door to a plethora of applications in fundamental and applied physics. With experiments routinely reaching the quantum regime, the focus has now turned towards creating and exploiting interesting non-classical states of motion and entanglement in optomechanical systems. Quantumness has also shifted from being the very reason why experiments are constructed to becoming a resource for the investigation of fundamental physics and the creation of quantum technologies. Here, by focusing on opto- and electromechanical platforms we review recent progress in quantum state preparation and entanglement of mechanical systems, together with applications to signal processing and transduction, quantum sensing and topological physics, as well as small-scale thermodynamics
Back-action ground state cooling of a micromechanical membrane via intensity-dependent interaction
We propose a theoretical scheme to show the possibility of achieving the
quantum ground state cooling of a vibrating micromechanical membrane inside a
high finesse optical cavity by back-action cooling approach. The scheme is
based on an intensity-dependent coupling of the membrane to the intracavity
radiation pressure field. We find the exact expression for the position and
momentum variances of the membrane by solving the linearized quantum Langevin
equations in the steady-state, conditioned by the Routh-Hurwitz criterion. We
show that by varying the Lamb-Dicke parameter and the membrane's reflectivity
one can effectively control the mean number of excitations of vibration of the
membrane and also cool down the system to micro-Kelvin temperatures
Converting microwave and telecom photons with a silicon photonic nanomechanical interface
Practical quantum networks require low-loss and noise-resilient optical
interconnects as well as non-Gaussian resources for entanglement distillation
and distributed quantum computation. The latter could be provided by
superconducting circuits but - despite growing efforts and rapid progress -
existing solutions to interface the microwave and optical domains lack either
scalability or efficiency, and in most cases the conversion noise is not known.
In this work we utilize the unique opportunities of silicon photonics, cavity
optomechanics and superconducting circuits to demonstrate a fully integrated,
coherent transducer connecting the microwave X and the telecom S bands with a
total (internal) bidirectional transduction efficiency of 1.2% (135 %) at
millikelvin temperatures. The coupling relies solely on the radiation pressure
interaction mediated by the femtometer-scale motion of two silicon nanobeams
and includes an optomechanical gain of about 20 dB. The chip-scale device is
fabricated from CMOS compatible materials and achieves a V as low as 16
V for sub-nanowatt pump powers. Such power-efficient, ultra-sensitive and
highly integrated hybrid interconnects might find applications ranging from
quantum communication and RF receivers to magnetic resonance imaging.Comment: 26 pages, 13 figure
Entangling optical and microwave cavity modes by means of a nanomechanical resonator
We propose a scheme that is able to generate stationary continuous-variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a nanomechanical resonator. We show that when both cavities are intensely driven, one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and optomechanical entanglement
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