Keränen Aarne, Chen Qi-Ming, Gunyhó András, Singh Priyank, Ma Jian, Vesterinen Visa, Govenius Joonas, Möttönen Mikko
QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto, Finland.
VTT Technical Research Centre of Finland Ltd. & QTF Centre of Excellence, P.O. Box 1000, Espoo, Finland.
Nat Commun. 2025 Apr 24;16(1):3875. doi: 10.1038/s41467-025-59230-2.
Microwave photons are essential carriers of quantum information in several promising platforms for quantum computing. However, measurement of the quantum statistical properties of microwave photons is demanding owing to their low energy relative to thermal fluctuations of any room-temperature detector, and phase-insensitive voltage amplification necessarily adds noise. Here, we overcome this trade-off with a nanobolometer that directly measures the photon statistics at millikelvin. Using a cryogenic temperature-controlled blackbody radiator, we demonstrate the detection of the mean photon number and reveal the expected photon number variance , following the Bose-Einstein distribution. By engineering the coherent and incoherent proportions of the input field, we observe a transition between super-Poissonian and Poissonian statistics from the bolometric second-order correlation measurements. This technique is poised to serve in fundamental tests of quantum mechanics and function as a scalable readout solution for a quantum information processor.
在几个有前景的量子计算平台中，微波光子是量子信息的重要载体。然而，由于微波光子相对于任何室温探测器的热涨落能量较低，测量其量子统计特性颇具挑战性，而且相位不敏感的电压放大必然会增加噪声。在此，我们利用一种纳米测辐射热计克服了这种权衡，该纳米测辐射热计能在毫开尔文温度下直接测量光子统计。通过使用低温控温黑体辐射器，我们演示了对平均光子数的检测，并揭示了符合玻色 - 爱因斯坦分布的预期光子数方差。通过设计输入场的相干和非相干比例，我们从测辐射热二阶关联测量中观察到超泊松统计和泊松统计之间的转变。这项技术有望用于量子力学的基础测试，并作为量子信息处理器的可扩展读出解决方案。
