{"id":254,"date":"2020-11-05T12:25:06","date_gmt":"2020-11-05T12:25:06","guid":{"rendered":"https:\/\/grasian.eu\/?page_id=254"},"modified":"2020-11-16T16:32:19","modified_gmt":"2020-11-16T16:32:19","slug":"gravitational-quantum-states","status":"publish","type":"page","link":"https:\/\/grasian.eu\/?page_id=254","title":{"rendered":"Gravitational Quantum States"},"content":{"rendered":"\n
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In this project, we will use Gravitational Quantum States (GQS<\/em>) of light neutral ultracold particles, hydrogen H<\/em> and neutrons n<\/em>. GQS<\/em> are formed with gravity on top and a specularly reflecting mirror with a sharply changing surface potential at the bottom. Particles move classically in the horizontal direction if the mixing of velocity components is small. As the masses of H<\/em> and n<\/em> are nearly equal, their energies and wave functions in GQS<\/em> are also nearly the same and characterized by ultralow energies (\u03b50<\/sub>~0.6peV<\/em>) and large sizes (l0<\/sub>~5.9\u03bcm<\/em>).<\/p>\n\n\n\n

GQS<\/em> were discovered with n<\/em> in 2002 [1-4] by a team led by V.Nesvizhevsky (see figure above from ref. 1, for references see the menu “Publications”), and since then they have been actively used by several groups (Tokyo, qBounce, GRANIT<\/em>) [6-9] to constrain theories with extra dimensions, new bosons, dark matter, etc. While repulsive n<\/em>-nuclei potentials [10] of materials produce reflection of ultracold n<\/em> from surfaces, attractive van der Waals\/Casimir-Polder (vdW\/C-P<\/em>) potentials also reflect ultracold atoms from surfaces due to quantum reflection [11-20]. These reflection processes have been studied in papers as early as 1936; since then they have given rise to fields of research with innumerable applications. The vdW\/C-P<\/em> surface potentials are also expected to reflect antiatoms [21-23] and form their GQS<\/em> [25-30]. Nobody has ever observed GQS<\/em> of atoms or anti-atoms. However, major motivations prompt efforts to observe and measure them with a maximum accuracy:<\/p>\n\n\n\n

     1. New fundamental interactions<\/em> (due to new bosons or other phenomena beyond Standard Model (SM<\/em>), manifestations of extra dimensions or dark matter [35-53,94]) would equally modify energies of GQS<\/em> of H<\/em> and n<\/em>. Extreme smallness of both GQS<\/em> energies (~1peV<\/em>) and contributions of other fundamental interactions provide the high sensitivity of GQS<\/em> to the presence of new interactions between particle and mirror. The sensitivity depends on GQS<\/em> lifetimes \u03c4<\/em> and particle phase-space densities \u03c1<\/em>. Evidently, studies with H<\/em> promise a dramatic increase of \u03c1<\/em>. Due to trapping, H<\/em> will also increase \u03c4<\/em> compared to those achieved with n<\/em>. Thus, studies with H<\/em> promise to surpass the current sensitivity with n<\/em>. Below we will address a strategy to improve n<\/em> experiments as well. The same arguments hold true for centrifugal quantum states (CQS<\/em>) [54], which are analogous to GQS<\/em> with the centrifugal acceleration replacing gravity and a curved mirror replacing a flat one.<\/p>\n\n\n\n

\u00a0\u00a0\u00a0\u00a0 2. Ongoing experiments with antihydrogen atoms at CERN<\/em> (AEGIS<\/em>, ALPHA<\/em>, GBAR<\/em>) [31-33] aim to measure the gravitational acceleration of antimatter. The most precise method proposed so far relies on GQS<\/em> of \u00a0in future experiments [27,34,96]; a projected accuracy is ~10-4<\/sup>-10-6<\/sup><\/em> depending on \u00a0densities achieved and a chosen measuring mode. A straightforward way to prove the existence of GQS<\/em> consists in performing measurements with H<\/em> to explore systematics and optimizing the techniques prior to starting resources-limited studies at CERN<\/em>. Thus, GRASIAN<\/em> is quite timely. Moreover, the planned periods of extended shutdowns of CERN<\/em> and ILL<\/em> will allow the PIs to focus on this project when needed.\u00a0<\/p>\n\n\n\n

     3. Using the methods developed with GQS<\/em>, we may accept large horizontal velocities, which are not relevant for the spectroscopic techniques we will use, but provide tremendous gain in statistics.<\/p>\n\n\n\n

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Observation time is the key parameter for improving the precision of measurements of GQS<\/em> of particles levitating above a reflecting surface. As one option to increase it, we propose a new method [111] of long confinement in such states of atoms, anti-atoms, neutrons and other particles possessing a magnetic moment. The earth gravitational field and a reflecting mirror confine particles in the vertical direction.
The magnetic field originating from electric current passing through a vertical wire confines particles in the radial direction. Under appropriate conditions, motions along these two directions are decoupled to a high degree. We estimate characteristic parameters of the problem, and list possible systematic effects that limit storage times due to the coupling of the two motions.<\/p>\n\n\n\n

For references see t<\/strong>he menu “Publications”.<\/h6>\n\n\n\n
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Back to Projects<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

In this project, we will use Gravitational Quantum States (GQS) of light neutral ultracold particles, hydrogen H and neutrons n. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":115,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"full-width-page.php","meta":[],"_links":{"self":[{"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/pages\/254"}],"collection":[{"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/grasian.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=254"}],"version-history":[{"count":59,"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/pages\/254\/revisions"}],"predecessor-version":[{"id":630,"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/pages\/254\/revisions\/630"}],"up":[{"embeddable":true,"href":"https:\/\/grasian.eu\/index.php?rest_route=\/wp\/v2\/pages\/115"}],"wp:attachment":[{"href":"https:\/\/grasian.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=254"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}