Definition of Sisyphus cooling

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Photonics Dictionary

Sisyphus cooling: Sisyphus cooling is a technique used in atomic physics to achieve ultracold temperatures of atoms or molecules by exploiting the periodic motion of particles in optical traps or lattices. The name Sisyphus is derived from the mythological figure Sisyphus, who was condemned to endlessly roll a boulder uphill, only for it to roll back down each time he neared the top, symbolizing the repetitive nature of the cooling process.

In Sisyphus cooling, the particles are trapped in a potential energy landscape created by laser beams, typically in the form of a one-dimensional optical lattice or a set of crossed laser beams. As the particles move in the trap, they interact with the laser light, experiencing periodic modulations of the trapping potential.

The cooling mechanism relies on the Doppler effect, which causes the frequency of scattered photons to shift depending on the relative velocity between the particles and the laser light. In Sisyphus cooling, the periodic modulation of the trapping potential leads to a cyclic variation in the particle's velocity, resulting in repeated absorption and emission of photons with frequency shifts that preferentially remove kinetic energy from the particles.

Through successive cycles of absorption and emission, the particles lose kinetic energy and are gradually cooled to ultracold temperatures, typically on the order of microkelvin (µK) or even nanokelvin (nK). Sisyphus cooling is particularly effective for cooling atoms or molecules with large optical cross-sections, such as alkali atoms, to temperatures close to the recoil limit, where the kinetic energy of the particles is comparable to the energy transferred in a single photon scattering event.

Sisyphus cooling is an important technique in the field of ultracold atomic physics and quantum optics, where ultracold temperatures are required to study phenomena such as Bose-Einstein condensation, degenerate Fermi gases, quantum degeneracy, and quantum information processing. It has applications in areas such as precision metrology, quantum simulation, and quantum computing.

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