Study on cooling of positronium for Bose–Einstein condensation

Shu, Kenji; Fan, X.; Yamazaki, T.; Namba, T.; Asai, S.; Yoshioka, Kosuke; Kuwata‐Gonokami, Makoto

doi:10.1088/0953-4075/49/10/104001

Cited by 29 publications

(21 citation statements)

References 32 publications

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“…This means that atoms cannot be selected according to their velocity, and laser cooling will be ineffective. Thus, while laser cooling for a confined Ps gas can be envisioned [676], the effects of confinement would have to be explicitly addressed, either by using sufficiently large cavities or other confining structures [123], or possibly by using alternative cooling schemes employing short-pulsed lasers (e.g. [677,678]).…”

Section: Bose-einstein Condensationmentioning

confidence: 99%

Experimental progress in positronium laser physics

2018

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Abstract. The field of experimental positronium physics has advanced significantly in the last few decades, with new areas of research driven by the development of techniques for trapping and manipulating positrons using Surko-type buffer gas traps. Large numbers of positrons (typically ≥10 6 ) accumulated in such a device may be ejected all at once, so as to generate an intense pulse. Standard bunching techniques can produce pulses with ns (mm) temporal (spatial) beam profiles. These pulses can be converted into a dilute Ps gas in vacuum with densities on the order of 10 7 cm −3 which can be probed by standard ns pulsed laser systems. This allows for the efficient production of excited Ps states, including long-lived Rydberg states, which in turn facilitates numerous experimental programs, such as precision optical and microwave spectroscopy of Ps, the application of Stark deceleration methods to guide, decelerate and focus Rydberg Ps beams, and studies of the interactions of such beams with other atomic and molecular species. These methods are also applicable to antihydrogen production and spectroscopic studies of energy levels and resonances in positronium ions and molecules. A summary of recent progress in this area will be given, with the objective of providing an overview of the field as it currently exists, and a brief discussion of some future directions.

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Section: Bose-einstein Condensationmentioning

confidence: 99%

Experimental progress in positronium laser physics

2018

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“…Other than probing structure and reaction mechanism of matters, the Ps formation is a unique pathway to the electron-positron annihilation process [3,4] with both astrophysical [5] and applied [6] interests. Possible production of Bose-Einstein condensate of Ps has also been predicted [7,8], besides the importance of Ps in diagnosing porous materials [9] as well as in probing bound-state QED effects [10]. Moreover, efficient Ps formation is the precursor of the production of dipositronium molecules [11] and antihydrogen atoms [12,13] required to study the effect of gravitational force on antimatter [14,15].…”

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confidence: 99%

Ubiquitous diffraction resonances in positronium formation from fullerenes

Hervieux

Chakraborty

2017

Phys. Rev. A

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Due to the dominant electron capture by positrons from the molecular wall and the spatial dephasing across the wall-width, a powerful diffraction effect universally underlies the positronium (Ps) formation from fullerenes. This results into trains of resonances in the Ps formation cross section as a function of the positron beam energy, producing uniform structures in recoil momenta in analogy with classical single-slit diffraction fringes in the configuration space. The prediction opens a hitherto unknown avenue of Ps spectroscopy with nanomaterials.PACS numbers: 34.80. Lx, 36.10.Dr, Following the impact of positrons with matter the formation of exotic electron-positron bound-pair, the positronium (Ps), is a vital process in nature. This channel accounts for as large as half of the positron scattering cross section from simple atoms and molecules [1], as well as an even higher success rate of Ps formation on surfaces and thin films [2]. Other than probing structure and reaction mechanism of matters, the Ps formation is a unique pathway to the electron-positron annihilation process [3,4] with both astrophysical [5] and applied [6] interests. Possible production of Bose-Einstein condensate of Ps has also been predicted [7,8], besides the importance of Ps in diagnosing porous materials [9] as well as in probing bound-state QED effects [10]. Moreover, efficient Ps formation is the precursor of the production of dipositronium molecules [11] and antihydrogen atoms [12,13] required to study the effect of gravitational force on antimatter [14,15].Theoretical investigations to calculate Ps formation cross sections from atomic hydrogen [16][17][18], noble gases [19][20][21], and alkali metals [22,23] However, in spite of such broad landscape of Ps research, little attempt of Ps formation by implanting positrons in nanoparticles, in gas or solid phase, has so far been made, except for a single theoretical study using Na clusters [36]. On the other hand, straddling the line between atoms and condensed matters are clusters and nanostructures that not only have hybrid properties of the two extremes, but also exhibit outstanding behaviors with unusual spectroscopic effects [37]. Formation of a quasi-free electron gas within a finite nanoscopic region of well-defined boundary, as opposed to a longer-range, highly diffused Coulomb-type boundary characteristic of atoms and molecules, is a property of nanosystems which ensures predominant electron capture from localized regions in space. This may lead to diffraction in the capture amplitude, particularly at positron energies that cannot excite plasmon modes. The Ps formation from fullerenes can be singularly attractive to access this diffraction phenomenon due to fullerene's eminent symmetry and stability, and its previous track record of success in spectroscopic experiments [38]. In this communication, we show that the Ps formation amplitude from the positron colliding with C 60 does include a strong diffraction effect, resulting in a system of peaks in the form of broad shape ...

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“…For this purpose, a Doppler laser cooling of o-Ps has been studied on the transition 1 3 S ↔ 2 3 P. This cooling process has been first studied by [23], and led to non conclusive experimental trials [24,25]. A recent publication [26] proposes a new method to cool Ps in order to reach a BEC. We present here simulation results of the Doppler cooling of o-Ps, performed to determine its feasibility within the AEgIS apparatus, with the dye-based laser systems we have.…”

Section: A Possible Laser Doppler Cooling Of Ps ?mentioning

confidence: 99%

Overview of Recent Work on Laser Excitation of Positronium for the Formation of Antihydrogen

Yzombard

Strojek

Evans

et al. 2017

Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)

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The AEgIS experiment carried out at CERN aims to form a cold antihydrogen beam to perform precision studies on gravity. A key ingredient is the creation of antihydrogen via a charge-exchange process between trapped antiprotons and Rydberg excited positronium atoms (Ps). In the present, the latest results of laser excitation of Ps are reviewed, as well as studies on a possible laser manipulation and cooling of Ps and antiprotons.

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Study on cooling of positronium for Bose–Einstein condensation

Cited by 29 publications

References 32 publications

Experimental progress in positronium laser physics

Experimental progress in positronium laser physics

Ubiquitous diffraction resonances in positronium formation from fullerenes

Overview of Recent Work on Laser Excitation of Positronium for the Formation of Antihydrogen

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