On-Demand Microwave Generator of Shaped Single Photons

Abstract

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. arXiv:1706.06688v2 [quant-ph]

Characterizing decoherence rates of a superconducting qubit by direct microwave scattering

“…Waveguide QED is also an enabling quantum technology. One of the key applications is to generate [13][14][15][16][17][18][19] and detect 4,[20][21][22][23][24][25][26] single photons. It has been proposed to use waveguide QED to create bound states [27][28][29] and implement quantum computers [30][31][32] .…”

Tunable Microwave Single-Photon Source Based on Transmon Qubit with High Efficiency

“…There have already been some implementations of single-photon sources, which are based on cavity QED systems [13][14][15][16][17]. Instead of confining the photons with a fixed cavity mode, recently several single-photon sources have also been demonstrated by strong coupling to one-dimensional (1D) continuum [18,19] and generating tunable single photons, using either flux qubits [20] or transmon qubits [21][22][23].…”

Effects of photon statistics in wave mixing on a single qubit

“…This source for quantum superpositions of vacuum and one photon can be engineered, for example, on the basis of ideas of Refs. 21,22 , where tunable single-photon sources constructed from artificial superconducting atoms were demonstrated. The emitter is periodically excited by a strong external drive, which brings it to quantum-mechanical superposition of lowest energy state |↓ and excited state |↑ with fixed weights.…”

“…nonclassical field that is produced either by degenerate parametric amplifier 10,20 or by a single-photon source [21][22][23] . We indeed find that peaks structure is not identical to the case of wave mixing of two continuous coherent waves -for example, some peaks turn out to be absent.…”