Quantum memory
[1] The interaction of quantum radiation with multiple particles has sparked scientific interest over the past decade.
In this case, a piece of paper, or a computer hard disk, can be used to store information on the lamp[clarification needed].
A team led by professor Du Shengwang of the department of physics at the Hong Kong University of science and technology[6] and William Mong Institute of Nano Science and Technology at HKUST[7] has found a way to increase the efficiency of optical quantum memory to more than 85 percent.
From a cybersecurity perspective, the magic of qubits is that if a hacker tries to observe them in transit, their fragile quantum states shatter.
[10] The nitrogen-vacancy center in diamond has attracted a lot of research in the past decade due to its excellent performance in optical nanophotonic devices.
In a recent experiment, electromagnetically induced transparency was implemented on a multi-pass diamond chip to achieve full photoelectric magnetic field sensing.
Alkali metal vapor isotopes of a large number of near-infrared wavelength optical depth, because they are relatively narrow spectrum line and the number of high density in the warm temperature of 50-100 ∘ C. Alkali vapors have been used in some of the most important memory developments, from early research to the latest results we are discussing, due to their high optical depth, long coherent time and easy near-infrared optical transition.
An atomic vapor quantum memory is ideal for storing such beams because the orbital angular momentum of photons can be mapped to the phase and amplitude of the distributed integration excitation.
Diffusion is a major limitation of this technique because the motion of hot atoms destroys the spatial coherence of the storage excitation.
Early successes included storing weakly coherent pulses of spatial structure in a warm, ultracold atomic whole.
In one experiment, the same group of scientists in a caesium magneto-optical trap was able to store and retrieve vector beams at the single-photon level.
[12] The memory preserves the rotation invariance of the vector beam, making it possible to use it in conjunction with qubits encoded for maladjusted immune quantum communication.
The first storage structure, a real single photon, was achieved with electromagnetically induced transparency in rubidium magneto-optical trap.
The dual-orbit setup also proves coherence in multimode memory, where a preannounced single photon stores the orbital angular momentum superposition state for 100 nanoseconds.
The experiment in a three-level system based on hot atomic vapor resulted in demonstration of coherent storage with efficiency up to 87%.
In contrast to other approaches, EIT has a long storage time and is a relatively easy and inexpensive solution to implement.
Experimental results show that in all these operations, the fidelity of the three-dimensional quantum state carried by the photon can be maintained at around 89%.
Nevertheless, diamond memory has allowed some revealing studies of the interactions between light and matter at the quantum level: optical phonons in a diamond can be used to demonstrate emission quantum memory, macroscopic entanglement, pre-predicted single-photon storage, and single-photon frequency manipulation.
Researchers at the University of Geneva in Switzerland working with France's CNRS have discovered a new material in which an element called ytterbium can store and protect quantum information, even at high frequencies.
