Subjects: Optics >> Quantum optics submitted time 2023-07-10
Abstract： The atomic system has reflection symmetry, parity, and atomic stimulated radiation amplified by a parallel plane resonant cavity, can generate macroscopic photons entangled state[4].
It is a quantum entangled state of 2N photons with a certain parity, a total momentum of zero, a certain energy, and a certain angular momentum. Observing it in time and space has uncertainty and randomness. According to the Heisenberg uncertainty principle, its energy (frequency) and momentum are completely determined. The measurement accuracy can reach the Heisenberg quantum limit and has a quantum 2N enhancement effect (2N is the number of entangled photons).
The probability distribution P2N （t） of ∣Ф2NI > and its fourier transform P2N （w-w0 ）were measured through experiments, and the experimental results were in line with theoretical expectations. And the lifetime of macroscopic photons entangled state was observed, which also has a 2N enhancement factor. The experimental results are consistent with theoretical expectations.
Peer Review Status:
Awaiting Review
Subjects: Optics >> Quantum optics submitted time 2023-06-25
Abstract： Multi-photon entanglement is the core technology of quantum information technology such as quantum computation and quantum communication. Two-photon entanglement generated by spontaneous parametric down-conversion is a commonly used source of entanglement. Entangled photons emit randomly, and the probability of entanglement pairs is very small. Although great achievements have been made, it is still far from the application requirements of quantum computing and other fields. New approaches need to be explored from two aspects of basic theory and experimental research.
In this paper, the fundamental process of stimulated radiation and the mechanism of stimulated radiation are studied. It is found that the quantum properties of the initial two-photon state produced by this process are closely related to the symmetry of the stimulated substances. If the electronic states of stimulated radiation substances have parity, their wave functions also have parity, such as atoms, molecules with symmetric centers, crystals with reflection symmetry, etc. The electronic states of these substances have parity and reflection symmetry. The stimulated radiation process of a parity substances obeys parity conservation. The two-photon state produced by the stimulated radiation has parity and is superposition entangled state. Such two entangled photons pass through the action of parallel plane resonator, and then through stimulated radiation, the process is repeated again and again, and finally produces multi-photon entanglement.
The main results and conclusions of this paper are as follows: multi-photon entangled state is generated by stimulated radiation of parity substances. If the electronic state of the laser substance has parity, the multi-photon state produced by the stimulated radiation in the laser resonator (parallel plane cavity) is entangled state and can be output from a symmetrical two-way single longitudinal mode laser.
The expression of multiphoton entanglement is given theoretically. A symmetrical bi-directional output single longitudinal mode He-Ne laser has been developed. The experimental verification of multi-photon entangled state has been carried out. The experimental results are in good agreement with the theoretical expectations.
Peer Review Status:Awaiting Review
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