9,127 research outputs found
Strongly interacting photons in one-dimensional continuum
Photon-photon scattering in vacuum is extremely weak. However, strong
effective interactions between single photons can be realized by employing
strong light-matter coupling. These interactions are a fundamental building
block for quantum optics, bringing many-body physics to the photonic world and
providing important resources for quantum photonic devices and for optical
metrology. In this Colloquium, we review the physics of strongly-interacting
photons in one-dimensional systems with no optical confinement along the
propagation direction. We focus on two recently-demonstrated experimental
realizations: superconducting qubits coupled to open transmission lines, and
interacting Rydberg atoms in a cold gas. Advancements in the theoretical
understanding of these systems are presented in complementary formalisms and
compared to experimental results. The experimental achievements are summarized
alongside a description of the quantum optical effects and quantum devices
emerging from them.Comment: Updated version, accepted for publication in Reviews of Modern
Physic
On the indistinguishability of Raman photons
We provide a theoretical framework to study the effect of dephasing on the
quantum indistinguishability of single photons emitted from a coherently driven
cavity QED -system. We show that with a large excited-state detuning,
the photon indistinguishability can be drastically improved provided that the
fluctuation rate of the noise source affecting the excited state is fast
compared with the photon emission rate. In some cases a spectral filter is
required to realize this improvement, but the cost in efficiency can be made
small.Comment: 18 pages, 3 figures, final versio
On-demand microwave generator of shaped single photons
We demonstrate the full functionality of a circuit that generates single
microwave photons on demand, with a wave packet that can be modulated with a
near-arbitrary shape. We achieve such a high tunability by coupling a
superconducting qubit near the end of a semi-infinite transmission line. A dc
superconducting quantum interference device shunts the line to ground and is
employed to modify the spatial dependence of the electromagnetic mode structure
in the transmission line. This control allows us to couple and decouple the
qubit from the line, shaping its emission rate on fast time scales. Our
decoupling scheme is applicable to all types of superconducting qubits and
other solid-state systems and can be generalized to multiple qubits as well as
to resonators.Comment: 10 pages, 7 figures. Published versio
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