Superconducting Single Microwave Photon Detector with Buffer Resonator
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Solution Overview
Problem
Current single-photon detectors in the microwave domain face challenges with high dark noise, sensitivity to photon arrival time, and long dead times, making them inefficient for detecting single microwave photons due to their low energy and the need for cryogenic operation.
Innovation Solution
A superconducting device with a quantum system, buffer resonator, and highly dissipative auxiliary resonator, coupled through parametric pumping, allows for efficient detection of single microwave photons by converting the incident photon into an excitation of the quantum system and dissipating the reverse process, enabling low dark noise and short dead times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-photon detection methods are used in the microwave domain, then detection can be performed, but dark noise becomes unacceptably high and detection efficiency drops
Solution Approach 1:
The detection process is segmented into distinct stages: photon capture by the qubit, state evolution during a defined interval, and measurement. This segmentation allows optimization of each stage independently, reducing dark noise while maintaining detection efficiency.
Solution Approach 2:
The detector operates in periodic cycles consisting of a detection window followed by a reset period. During the detection window, the qubit is monitored for photon absorption; afterward, the qubit is reset to its ground state. This periodic operation prevents accumulation of errors and reduces dark noise.
2Productivity
If the detection window is extended to capture more photons, then detection coverage improves, but dark noise increases intrinsically
Solution Approach 1:
The detection process uses periodic measurement cycles with well-defined detection windows followed by reset periods. This allows the system to accumulate detection coverage over multiple cycles while resetting between cycles prevents dark noise accumulation, resolving the contradiction between extended detection coverage and dark noise control.
Solution Approach 2:
The detector achieves continuous operational capability through rapid reset mechanisms that prepare the qubit for the next detection cycle. This continuity allows extended effective detection coverage while maintaining low dark noise through systematic resetting, rather than requiring a single extended measurement window.
3Measurement precision
If intensity modulation is used to capture photons, then detection precision improves, but the detector becomes sensitive to photon arrival time and temporal form
Solution Approach 1:
The qubit is prepared in a known ground state before each detection window, establishing a predetermined initial condition. This preliminary preparation eliminates the need for precise knowledge of photon arrival time or temporal form, as the detection relies only on whether the qubit transitions from ground to excited state during the measurement interval.
Solution Approach 2:
The detection method changes from intensity-based modulation to state-based detection. Instead of modulating the intensity of the conversion process to match photon temporal characteristics, the system detects the quantum state transition of the qubit, which is insensitive to the temporal form of the incident photon.
4Reliability
If permanent measurement of the qubit state is performed, then detection occurs, but detection efficiency reduces and dead time increases
Solution Approach 1:
The measurement is performed periodically at the end of defined detection windows rather than continuously. After each measurement and subsequent reset, the system enters a waiting period during which no measurement occurs. This periodic approach reduces dead time compared to permanent continuous measurement while ensuring detection occurs at appropriate intervals.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high detection efficiency with low dark noise and short dead times, allowing for continuous operation and improved detection capabilities in the microwave frequency band without requiring precise timing of the photon arrival.
Implementation Method 1
the incident photon to be detected is converted into an excitation of a quantum system with two energy levels
Implementation Method 2
This frequency band requires working in a cryogenic environment (∼10 mK) so that the thermal noise is well below the energy of a photon
Implementation Method 3
the photon of the auxiliary resonator is dissipated
Data Source
AI summary
A superconducting detection device for detecting a single microwave photon, including: —a quantum system with two energy levels of which the ground state and an excited state are controllable and detectable, the quantum system being designed to allow modulable three-wave interaction; —a buffer resonator arranged to receive an incident single microwave photon; —a highly dissipative auxiliary resonator arranged to discharge a photon; and —a reading device arranged to detect the state of the two-level quantum system; the buffer resonator and the auxiliary resonator are coupled to the quantum system; and the excited state of the quantum system and the photon of the auxiliary resonator are created in response to the reception of the incident photon in the buffer resonator and to the application of parametric pumping to the device. A method for detecting a single microwave photon implemented by a device according to the invention.