18 research outputs found
Optimal state estimation for cavity optomechanical systems
We demonstrate optimal state estimation for a cavity optomechanical system
through Kalman filtering. By taking into account nontrivial experimental noise
sources, such as colored laser noise and spurious mechanical modes, we
implement a realistic state-space model. This allows us to obtain the
conditional system state, i.e., conditioned on previous measurements, with
minimal least-square estimation error. We apply this method for estimating the
mechanical state, as well as optomechanical correlations both in the weak and
strong coupling regime. The application of the Kalman filter is an important
next step for achieving real-time optimal (classical and quantum) control of
cavity optomechanical systems.Comment: replaced with published version, 5+12 page
Development of a Boston-area 50-km fiber quantum network testbed
Distributing quantum information between remote systems will necessitate the
integration of emerging quantum components with existing communication
infrastructure. This requires understanding the channel-induced degradations of
the transmitted quantum signals, beyond the typical characterization methods
for classical communication systems. Here we report on a comprehensive
characterization of a Boston-Area Quantum Network (BARQNET) telecom fiber
testbed, measuring the time-of-flight, polarization, and phase noise imparted
on transmitted signals. We further design and demonstrate a compensation system
that is both resilient to these noise sources and compatible with integration
of emerging quantum memory components on the deployed link. These results have
utility for future work on the BARQNET as well as other quantum network
testbeds in development, enabling near-term quantum networking demonstrations
and informing what areas of technology development will be most impactful in
advancing future system capabilities.Comment: 9 pages, 5 figures + Supplemental Material
Telecom networking with a diamond quantum memory
Practical quantum networks require interfacing quantum memories with existing
channels and systems that operate in the telecom band. Here we demonstrate
low-noise, bidirectional quantum frequency conversion that enables a
solid-state quantum memory to directly interface with telecom-band systems. In
particular, we demonstrate conversion of visible-band single photons emitted
from a silicon-vacancy (SiV) center in diamond to the telecom O-band,
maintaining low noise () and high indistinguishability
(). We further demonstrate the utility of this system for quantum
networking by converting telecom-band time-bin pulses, sent across a lossy and
noisy 50 km deployed fiber link, to the visible band and mapping their quantum
states onto a diamond quantum memory with fidelity .
These results demonstrate the viability of SiV quantum memories integrated with
telecom-band systems for scalable quantum networking applications.Comment: 9 pages, 5 figures + Supplemental Material
Single Phonon Quantum Optics
Akustische Phononen, die energetischen Eigenzustände von mechanischen Vibrationen, besitzen eine Vielzahl an interessanten Eigenschaften für die Verarbeitung von Quanteninformation. Beispielsweise können sie als langlebige und kompakte Quanteninformationsspeicher eingesetzt werden, oder Quantenzustände zwischen anderweitig inkompatiblen
Systemen übertragen. Aufgrund ihrer technischen Relevanz sind hierbei Photonen im
optischen Telekommunikations-Frequenzband von besonderem Interesse. Mit Hilfe von künstlich erzeugten optischen und akustischen Resonanzen, können die Photonen mit Phononen mittels Strahlungsdruck interagieren. Jedoch war die Kontrolle einzelner Bewegungsanregungen in mikromechanischen Resonatoren bisher auf den Mikrowellenbereich
beschränkt, wohingegen das Ziel einer Manipulation durch Laser unerreicht blieb. In
dieser Dissertation beschreibe ich, wie dies experimentell mithilfe von quantenoptischen
Protokollen erreicht werden kann. Zunächst wird gezeigt, dass optomechanische Kristalle im Quantenbereich betrieben werden können, indem nichtklassische Photon-Phonon Paare mittels optomechanischer parametrischer Fluoreszenz erzeugt werden. Diese Quantenschnittstelle wird daraufhin verwendet um einzelne Phononen zu charakterisieren, sowie Quantenverschränkung zwischen zwei entfernten mechanischen Oszillatoren zu erzeugen.
Die Demonstration dieser klassischen Quantenoptik Experimente mit einzelnen Phononen zeigt, dass mechanische Quanteninformationsspeicher eine vielversprechende Ressource
für künftige Quantennetzwerke darstellen.Acoustic phonons, the energy eigenstates of mechanical vibrations, possess a plethora of interesting features for quantum information processing.
For example, they can serve as compact quantum memories with long life times, or can transduce quantum states between a variety of otherwise incompatible quantum systems.
Particularly interesting among those are infrared photons in the telecommunication wavelength band, due to their widespread use in quantum communication. Using artificial optical and mechanical resonances, they can interact with phonons by radiation pressure.
However, controlling individual excitations of motion in micromechanical resonators has thus far been restricted to the domain of microwave radiation, while optical control remained an outstanding goal.
In this thesis, I describe how this can be achieved experimentally, employing quantum optics protocols.
First, the operation of silicon optomechanical crystals in the quantum regime is demonstrated by creating non-classical photon-phonon pairs through optomechanical down conversion.
This quantum interface is subsequently used to characterize heralded single phonons, and to generate quantum entanglement between two remote mechanical oscillators.
The realization of these classic quantum optics experiments with single phonons establishes mechanical quantum memories in silicon photonics as a useful resource for future quantum networks