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Physical Review A

Nonreciprocity detector arrays for high-efficiency detection of itinerant microwave photons

Suirong He, P. H. Ouyang, Haiyan Gao, Yufen Li, Jiaxing He, L. F. Wei

Published Jun 24, 2024• 3 citations
Publisher

Abstract

Microwave single-photon detection is one of the critical tasks for the implementation of the desired microwave quantum information processing. Given the detection efficiency of the demonstrated microwave single-photon detector is still very limited, here, we propose a nonreciprocity detector array to implement high-efficiency detection of a single itinerant microwave photon, transported along a one-dimensional waveguide. We show that different from the reciprocity array with more than 20 atomic detectors [Romero et al., Phys. Rev. Lett. 102, 173602 (2009)] for ideal detection, the nonreciprocity array with just three atomic detectors is sufficient to achieve deterministic detection (i.e., the achievable probability approaches $100%$) of a single itinerant microwave photon. Specifically, we design an array with a few current-biased Josephson junctions individually coupled to a common microwave transmission line and then discuss its feasibility.

DOI
10.1103/physreva.109.062430

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Microwave single-photon detection is one of the critical tasks for the implementation of the desired microwave quantum information processing. Given the detection efficiency of the demonstrated microwave single-photon detector is still very limited, here, we propose a nonreciprocity detector array to implement high-efficiency detection of a single itinerant microwave photon, transported along a one-dimensional waveguide. We show that different from the reciprocity array with more than 20 atomic detectors [Romero et al., Phys. Rev. Lett. 102, 173602 (2009)] for ideal detection, the nonreciprocity array with just three atomic detectors is sufficient to achieve deterministic detection (i.e., the achievable probability approaches 100100%100) of a single itinerant microwave photon. Specifically, we design an array with a few current-biased Josephson junctions individually coupled to a common microwave transmission line and then discuss its feasibility.
Single-photon detection plays important roles in implementing desired quantum information processing. In this work, we propose a single itinerant photon detector based on absorption by two interacting atoms coupling to a waveguide, which can work in the microwave regime. Both the cases of giant and small atoms are considered. Each atom is modeled as a three-level system, with only one transition coupling to the waveguide. Our analysis reveals that, for a single atom coupled to the waveguide, the maximum detection probability is intrinsically limited to 0.5. This limit, however, can be lifted under perfectly chiral coupling, where unit detection probability becomes achievable. For the non-chiral case, we show that when a giant molecule consisting of two giant atoms with direct interaction couples to the waveguide, the single-photon detection probability can reach the ideal value of 1. Furthermore, we extend the model to the regime of small atoms and show that perfect single-photon detection remains attainable by appropriately tuning the direct coupling strength and the interatomic separation. These results provide a feasible route toward high-efficiency microwave single-photon detection based on engineered atom-waveguide interactions.
We present a novel scheme to detect itinerant microwave radiation at the single photon level. Using existing Josephson-photonics devices, where two microwave cavities are coupled by a dc-voltage biased superconducting junction, we theoretically show how to implement a stroboscopically repeated, near-projective measurement of a photon impinging on one of the cavities. Optimizing rate, duration, and strength of the measurement by flux control of the junction and developing a threshold protocol to detect the photon from a homodyne measurement of the radiation output of the other cavity, we achieve highly efficient detection with low dark counts. By cascading the detector with a preamplifier, where a similar two-cavity Josephson-photonics device acts as a photon multiplier, we can further improve the device to reach a detection efficiency of 88.5%88.5 \%88.5% with a dark count rate of ∼10−4γa\sim10^{-4} γ_a∼10−4γa​, set by the resonance width γaγ_aγa​ of the absorbing cavity. These results for a multiplication factor of two suggest that near-unity efficiencies may be reached for higher multiplication factors.
In order to apply all ideas from quantum optics to the field of quantum circuits, one of the missing ingredients is a high-efficiency single-photon detector. In this work we propose a design for such a device which successfully reaches 100% efficiency with only one absorber. Our photon detector consists of a three-level system (a phase qubit) coupled to a semi-infinite one-dimensional waveguide (a microwave transmission line) which performs highly efficient photodetection in a simplified manner as compared to previous proposals. Using the tools of quantum optics we extensively study the scattering properties of realistic wave packets against this device, thereby computing the efficiency of the detector. We find that the detector has many operating modes, can detect detuned photons, is robust against design imperfections, and can be made broadband by using more than one absorbing element in the design. Many of these ideas could be translated to other single-mode photonic or plasmonic waveguides interacting with three-level atoms or quantum dots.
The realization of a high-efficiency microwave single photon detector is a long-standing problem in the field of microwave quantum optics. Here, we propose a quantum nondemolition, high-efficiency photon detector that can readily be implemented in present state-of-the-art circuit quantum electrodynamics. This scheme works in a continuous fashion, gaining information about the photon arrival time as well as about its presence. The key insight that allows us to circumvent the usual limitations imposed by measurement backaction is the use of long-lived dark states in a small ensemble of inhomogeneous artificial atoms to increase the interaction time between the photon and the measurement device. Using realistic system parameters, we show that large detection fidelities are possible.
Single-photon detection is an essential component in many experiments in quantum optics, but it remains challenging in the microwave domain. We realize a quantum nondemolition detector for propagating microwave photons and characterize its performance using a single-photon source. To this aim, we implement a cavity-assisted conditional phase gate between the incoming photon and a superconducting artificial atom. By reading out the state of this atom in a single shot, we reach an external (internal) photon-detection fidelity of 50% (71%), limited by transmission efficiency between the source and the detector (75%) and the coherence properties of the qubit. By characterizing the coherence and average number of photons in the field reflected off the detector, we demonstrate its quantum nondemolition nature. We envisage applications in generating heralded remote entanglement between qubits and for realizing logic gates between propagating microwave photons.
Detecting an itinerant microwave photon with high efficiency is an outstanding problem in microwave photonics and its applications. We present a scheme to detect an itinerant microwave photon in a transmission line via the nonlinearity provided by a transmon in a driven microwave resonator. With a single transmon we achieve 84% distinguishability between zero and one microwave photons and 90% distinguishability with two cascaded transmons by performing continuous measurements on the output field of the resonator. We also show how the measurement diminishes coherence in the photon number basis thereby illustrating a fundamental principle of quantum measurement: The decoherence rate increases as the detector is made more effective.