80 research outputs found
Tunable slowing, storing and releasing of a weak microwave field
We study the slowing, storing and releasing of microwave pulses in a
superconducting circuits composed of two coplanar waveguide resonators and a
superconducting transmon-type qubit. The quantum interference analogy to
electromagnetically induced transparency is created in two coupled resonators.
By tuning the resonance frequency of the transmon, we dynamically tune the
effective coupling between the resonators. Via the modulation of the coupling,
we show the tunable true time delay of microwave pulses at the single-photon
level. We also store the microwave field in a high-Q resonator and release the
signal from it to the output port. Our scheme promises applications in both
quantum information processing and classical wireless communications.Comment: 16 pages, 9 figures, articl
Solid state optical interconnect between distant superconducting quantum chips
We propose a design for a quantum interface exploiting the electron spins in
crystals to swap the quantum states between the optical and microwave. Using
sideband driving of a superconducting flux qubit and a combined
cavity/solid-state spin ensemble Raman transition, we demonstrate how a
stimulated Raman adiabatic passage (STIRAP)-type operation can swap the quantum
state between a superconducting flux qubit and an optical cavity mode with a
fidelity higher than . We further consider two distant superconducting
qubits with their respective interfaces joined by an optical fiber and show a
quantum transfer fidelity exceeding between the two distant qubits.Comment: 5 figures, 5 page
Quantum Non-Demolition Measurement of Photons
According to Heisenberg’s uncertainty principle, measurement of a quantum observable introduces noise to this observable and thus limits the available precision of measurement. Quantum non-demolition measurements are designed to circumvent this limitation and have been demonstrated in detecting the photon flux of classical light beam. Quantum non-demolition measurement of a single photon is the ultimate goal because it is of great interest in fundamental physics and also a powerful tool for applications in quantum information processing. This chapter presents a brief introduction of the history and a review of the progress in quantum non-demolition measurement of light. In particular, a detailed description is presented for two works toward cavity-free schemes of quantum non-demolition measurement of single photons. Afterward, an outlook of the future in this direction is given
Detection of a weak magnetic field via cavity enhanced Faraday rotation
We study the sensitive detection of a weak static magnetic field via Faraday
rotation induced by an ensemble of spins in a bimodal degenerate microwave
cavity. We determine the limit of the resolution for the sensitivity of the
magnetometry achieved using either single-photon or multiphoton inputs. For the
case of a microwave cavity containing an ensemble of Nitrogen-vacancy defects
in diamond, we obtain a magnetometry sensitivity exceeding
0.5~\text{\nano\tesla}/\sqrt{\text{\hertz}}, utilizing a single photon probe
field, while for a multiphoton input we achieve a sensitivity about 1
\text{\femto\tesla}/\sqrt{\text{\hertz}}, using a coherent probe microwave
field with power of P_\text{in}=1~\text{\nano\watt}.Comment: 8 pages, 7 figure
Optical Chirality and Single-Photon Isolation
Optical isolation is important for protecting a laser from damage due to the detrimental back reflection of light. It typically relies on breaking Lorentz reciprocity and normally is achieved via the Faraday magneto-optical effect, requiring a strong external magnetic field. Single-photon isolation, the quantum counterpart of optical isolation, is the key functional component in quantum information processing, but its realization is challenging. In this chapter, we present all-optical schemes for isolating the backscattering from single photons. In the first scheme, we show the single-photon isolation can be realized by using a chiral quantum optical system, in which a quantum emitter asymmetrically couples to nanowaveguide modes or whispering-gallery modes with high optical chirality. Secondly, we propose a chiral optical Kerr nonlinearity to bypass the so-called dynamical reciprocity in nonlinear optics and then achieve room-temperature photon isolation with low insertion loss. The concepts we present may pave the way for quantum information processing in an unconventional way
Cavity-free nondestructive detection of a single optical photon
Detecting a single photon without absorbing it is a long standing challenge
in quantum optics. All experiments demonstrating the nondestructive detection
of a photon make use of a high quality cavity. We present a cavity free scheme
for nondestructive single-photon detection. By pumping a nonlinear medium we
implement an inter-field Rabi-oscillation which leads to a ?pi phase shift on
weak probe coherent laser field in the presence of a single signal photon
without destroying the signal photon. Our cavity-free scheme operates with a
fast intrinsic time scale in comparison with similar cavity-based schemes. We
implement a full real-space multimode numerical analysis of the interacting
photonic modes and confirm the validity of our nondestructive scheme in the
multimode case.Comment: 4 figures, 5 page
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