Positronium laser cooling in a magnetic field

Zimmer, Christian; Yzombard, P.; Camper, Antoine; Comparat, D.

doi:10.1103/physreva.104.023106

Cited by 9 publications

(1 citation statement)

References 48 publications

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“…melt the solid target. A second problem is that the cooling time of the Ps is proportional to the effective mass of the atoms in the cavity walls times the mean free path of the Ps in the cavity, and it would be difficult to obtain a below room temperature gas in a 100 nm diameter cavity within one mean lifetime [10] without laser cooling [7,11,12]. Another main concern is the recent report of Cooper et al [13] that Ps atoms inside such a cavity will likely become stuck to the inner walls of the cavity at room temperature and therefore might not be able to form a Boltzmann gas, let alone a BEC, in the vacuum space of the cavity.…”

Section: Introductionmentioning

confidence: 99%

Conditions for obtaining positronium Bose–Einstein condensation in a micron-sized cavity

et al. 2022

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The quest for making a triplet positronium (Ps) Bose–Einstein condensate confined in a micron-sized cavity in a material such as porous silica faces at least three interrelated problems: (1) About $$10^7$$ 10 7 spin polarized Ps atoms must be injected into a small cavity within a porous solid material without vaporizing it. (2) It is known that Ps atoms confined in 30–100 nm diameter cavities in porous silica do not remain in the gas phase, but become stuck to the cavity walls at room temperature (Cooper et al., Phys. Rev. B 97:205302, 2018). (3) Cooling a gas of Ps atoms to cryogenic temperatures by energy exchange with the walls would be a very slow process (Saito and Hyodo, in: Surko, Gianturco (eds) New Directions in Antimatter Chemistry and Physics, Springer Dordrecht, Netherlands, 2001) because of the relatively low collision rate with the walls and the large mismatch between the masses of the Ps and the wall atoms. A possible solution of these difficulties is presented, based on cooling the implanted positrons in an isotopically pure diamond single crystal target, subsequent saturating of the wall Ps coverage so that a substantial portion of the Ps will be in the gaseous state, and thermalizing the gas-phase Ps via collisions with the low effective mass wall Ps. A design process for the target material is outlined as well, including preliminary results in porous cavity fabrication using focused ion beam milling. Graphical abstract

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Section: Introductionmentioning

confidence: 99%

Conditions for obtaining positronium Bose–Einstein condensation in a micron-sized cavity

et al. 2022

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A fiber detector to monitor ortho-Ps formation and decay

Rienäcker

Brusa

Caravita

et al. 2022

Nuclear Instruments and Methods in Physics Research Section A:

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Cooling positronium to ultralow velocities with a chirped laser pulse train

Shu,

Tajima,

Uozumi

et al. 2024

Nature

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When laser radiation is skilfully applied, atoms and molecules can be cooled1–3, allowing the precise measurements and control of quantum systems. This is essential for the fundamental studies of physics as well as practical applications such as precision spectroscopy4–7, ultracold gases with quantum statistical properties8–10 and quantum computing. In laser cooling, atoms are slowed to otherwise unattainable velocities through repeated cycles of laser photon absorption and spontaneous emission in random directions. Simple systems can serve as rigorous testing grounds for fundamental physics—one such case is the purely leptonic positronium11,12, an exotic atom comprising an electron and its antiparticle, the positron. Laser cooling of positronium, however, has hitherto remained unrealized. Here we demonstrate the one-dimensional laser cooling of positronium. An innovative laser system emitting a train of broadband pulses with successively increasing central frequencies was used to overcome major challenges posed by the short positronium lifetime and the effects of Doppler broadening and recoil. One-dimensional chirp cooling was used to cool a portion of the dilute positronium gas to a velocity distribution of approximately 1 K in 100 ns. A major advancement in the field of low-temperature fundamental physics of antimatter, this study on a purely leptonic system complements work on antihydrogen13, a hadron-containing exotic atom. The successful application of laser cooling to positronium affords unique opportunities to rigorously test bound-state quantum electrodynamics and to potentially realize Bose–Einstein condensation14–18 in this matter–antimatter system.

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Positronium laser cooling in a magnetic field

Cited by 9 publications

References 48 publications

Conditions for obtaining positronium Bose–Einstein condensation in a micron-sized cavity

Conditions for obtaining positronium Bose–Einstein condensation in a micron-sized cavity

A fiber detector to monitor ortho-Ps formation and decay

Cooling positronium to ultralow velocities with a chirped laser pulse train

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