Spatially resolved single photon detection with a quantum sensor array

Abstract

We propose a method of resolving a spatially coherent signal, which contains on average just a single photon, against the background of local noise at the same frequency. The method is based on detecting the signal simultaneously in several points more than a wavelength apart through the entangling interaction of the incoming photon with the quantum metamaterial sensor array. The interaction produces the spatially correlated quantum state of the sensor array, characterised by a collective observable (e.g., total magnetic moment), which is read out using a quantum nondemolition measurement. We show that the effects of local noise (e.g., fluctuations affecting the elements of the array) are suppressed relative to the signal from the spatially coherent field of the incoming photon as , where N is the number of array elements. The realisation of this approach in the microwave range would be especially useful and is within the reach of current experimental techniques.

Field-based Design of a Resonant Dielectric Antenna for Coherent Spin-Photon Interfaces

“…While we considered a diamond membrane here, the design applies to diverse materials such as Si or GaAs. We anticipate that this design methodology and the resulting efficient quantum emitter interfaces will benefit numerous applications, including multiplexed quantum repeaters [29], arrayed quantum sensors [15,30], boson sampling [31], and spin-based fault-tolerant quantum computers [8].…”

Towards the Heisenberg limit in microwave photon detection by a qubit array

“…The fast progress in quality and complexity of experimentally realized superconducting qubit arrays coupled to waveguides [10][11][12][13][14][15] as well as in theory of these quantum metamaterials [16][17][18][19] stimulated the inquiry into the practical possibility of their application to single photon detection. It was shown 20 that for an array of N uncorrelated, non-interacting qubits used for a quantum non-demolition detection of a photon, the signal-to-noise ratio (SNR) ratio grows as √ N , corresponding to standard quantum limit (SQL), and it was suggested 21 that introducing some specific quantum correlations could realize the so-called Heisenberg limit for SNR, i.e., to have SNR scaling as N rather than √ N . Essentially, SQL is not the fundamental limit on the accuracy achieved by N measurements of the system (in parallel or consecutively).…”

Renninger’s Gedankenexperiment, the collapse of the wave function in a rigid quantum metamaterial and the reality of the quantum state vector

“…In a similar way, an off-resonance photon interacting with an array of quantum bits is predicted to produce identical phase shifts in their states, which affects the collective variable of the array (e.g., its total magnetic moment) and can be read out even if the photon is not absorbed 12 , providing another example of a quantum non-demolition measurement.…”