1. Measurement of microwave photon correlations at millikelvin with a thermal detector
- Author
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Keränen, Aarne, Chen, Qi-Ming, Gunyhó, András, Singh, Priyank, Ma, Jian, Vesterinen, Visa, Govenius, Joonas, and Möttönen, Mikko
- Subjects
Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Microwave photons are important carriers of quantum information in many promising platforms for quantum computing. They can be routinely generated, controlled, and teleported in experiments, indicating a variety of applications in quantum technology. However, observation of quantum statistical properties of microwave photons remains demanding: The energy of several microwave photons is considerably smaller than the thermal fluctuation of any room-temperature detector, while amplification necessarily induces noise. Here, we present a measurement technique with a nanobolometer that directly measures the photon statistics at millikelvin and overcomes this trade-off. We apply our method to thermal states generated by a blackbody radiator operating in the regime of circuit quantum electrodynamics. We demonstrate the photon number resolvedness of the nanobolometer, and reveal the n(n+1)-scaling law of the photon number variance as indicated by the Bose--Einstein distribution. By engineering the coherent and incoherent proportions of the input field, we observe the transition between super-Poissonian and Poissonian statistics of the microwave photons from the bolometric second-order correlation measurement. This technique is poised to serve in fundamental tests of quantum mechanics with microwave photons and function as a scalable readout solution for a quantum information processor.
- Published
- 2024