素粒子物理国際研究センター

“Quantum dark optics of axions: how can dark matter axion generate quantized photons?”

Speaker：

Dr. Akira Miyazaki（CNRS/IN2P3/IJCLab Universite Paris-Saclay, Research engineer）

Date：

Monday, 23 December, 2024

Time：

1:00pm-2:30pm JST（lecture + Q&A）

Place：

ICEPP meeting room#1017

Abstract：
Axion, originally proposed for solving the strong CP problem, has recently been gaining attentions as a promising light dark matter candidate. A distinct property of axions compared to WIMPS is its classical wave nature. Although axions have been searched via a classical wave detection scheme (linear amplifier, mixer, I/Q sampling, Fast Fourier Transform), quantum detectors (qubit, Transition Edge Sensor, etc) are proposed to overcome the standard quantum limit of classical methods. A fundamental question arises here: what is the quantum statistical distribution of the photon fields generated by the Primakoff effect out of classical axions? Do we need quantum statistical information on dark matter? Such an argument is of crucial importance to calculate a projective measurement of the photon field with a quantum detector. What is the relation between classical axion and quantum photon fields? In this seminar, we first review quantum (WIMP) and classical (axion) dark matter experiments. We introduce the famous argument on classicality of Schrodinger's wave packet and describe its modern representation with creation and annihilation operators: quantum coherent state. Then, we apply the Glauber's Theorem in Quantum Optics to the axion and prove that the influence of classical axion fields is represented by a displacement operator; thus, an axion field generates a wave packet of photons inside a cavity in the QED vacuum state. More generally, the generated photon field is a so-called thermal coherent state, and its quantum statistical nature will be fully revealed. Interestingly, this is not a simple Poissonian. If time allows, recent results of the MADMAX project by using state-of-the-art classical techniques will be shown together with perspective with quantum detections in the future.