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- ItemCold atoms in space: community workshop summary and proposed road-map(Berlin ; Heidelberg [u.a.] : Springer Open, 2022) Alonso, Iván; Alpigiani, Cristiano; Altschul, Brett; Araújo, Henrique; Arduini, Gianluigi; Arlt, Jan; Badurina, Leonardo; Balaž, Antun; Bandarupally, Satvika; Barish, Barry C.; Barone, Michele; Reguzzoni, Mirko; Richaud, Andrea; Riou, Isabelle; Rothacher, Markus; Roura, Albert; Ruschhaupt, Andreas; Sabulsky, Dylan O.; Safronova, Marianna; Saltas, Ippocratis D.; Bernabeu, Jose; Haehnelt, Martin; Salvi, Leonardo; Sameed, Muhammed; Saurabh, Pandey; Schäffer, Stefan; Schiller, Stephan; Schilling, Manuel; Schkolnik, Vladimir; Schlippert, Dennis; Schmidt, Piet O.; Schnatz, Harald; Hanımeli, Ekim T.; Bertoldi, Andrea; Schneider, Jean; Schneider, Ulrich; Schreck, Florian; Schubert, Christian; Shayeghi, Armin; Sherrill, Nathaniel; Shipsey, Ian; Signorini, Carla; Singh, Rajeev; Hawkins, Leonie; Singh, Yeshpal; Bingham, Robert; Skordis, Constantinos; Smerzi, Augusto; Sopuerta, Carlos F.; Sorrentino, Fiodor; Sphicas, Paraskevas; Stadnik, Yevgeny V.; Stefanescu, Petruta; Tarallo, Marco G.; Hees, Aurélien; Tentindo, Silvia; Tino, Guglielmo M.; Bize, Sébastien; Tinsley, Jonathan N.; Tornatore, Vincenza; Treutlein, Philipp; Trombettoni, Andrea; Tsai, Yu-Dai; Tuckey, Philip; Uchida, Melissa A.; Henderson, Victoria A.; Valenzuela, Tristan; Van Den Bossche, Mathias; Vaskonen, Ville; Blas, Diego; Verma, Gunjan; Vetrano, Flavio; Vogt, Christian; von Klitzing, Wolf; Waller, Pierre; Walser, Reinhold; Herr, Waldemar; Wille, Eric; Williams, Jason; Windpassinger, Patrick; Wittrock, Ulrich; Bongs, Kai; Wolf, Peter; Woltmann, Marian; Wörner, Lisa; Xuereb, André; Yahia, Mohamed; Herrmann, Sven; Yazgan, Efe; Yu, Nan; Zahzam, Nassim; Zambrini Cruzeiro, Emmanuel; Zhan, Mingsheng; Bouyer, Philippe; Zou, Xinhao; Zupan, Jure; Zupanič, Erik; Braitenberg, Carla; Hird, Thomas; Brand, Christian; Braxmaier, Claus; Bresson, Alexandre; Buchmueller, Oliver; Budker, Dmitry; Bugalho, Luís; Burdin, Sergey; Cacciapuoti, Luigi; Callegari, Simone; Calmet, Xavier; Hobson, Richard; Calonico, Davide; Canuel, Benjamin; Caramete, Laurentiu-Ioan; Carraz, Olivier; Cassettari, Donatella; Chakraborty, Pratik; Chattopadhyay, Swapan; Chauhan, Upasna; Chen, Xuzong; Chen, Yu-Ao; Hock, Vincent; Chiofalo, Maria Luisa; Coleman, Jonathon; Corgier, Robin; Cotter, J. P.; Michael Cruise, A.; Cui, Yanou; Davies, Gavin; De Roeck, Albert; Demarteau, Marcel; Derevianko, Andrei; Barsanti, Michele; Di Clemente, Marco; Djordjevic, Goran S.; Donadi, Sandro; Doré, Olivier; Dornan, Peter; Doser, Michael; Drougakis, Giannis; Dunningham, Jacob; Easo, Sajan; Eby, Joshua; Hogan, Jason M.; Elertas, Gedminas; Ellis, John; Evans, David; Examilioti, Pandora; Fadeev, Pavel; Fanì, Mattia; Fassi, Farida; Fattori, Marco; Fedderke, Michael A.; Felea, Daniel; Holst, Bodil; Feng, Chen-Hao; Ferreras, Jorge; Flack, Robert; Flambaum, Victor V.; Forsberg, René; Fromhold, Mark; Gaaloul, Naceur; Garraway, Barry M.; Georgousi, Maria; Geraci, Andrew; Holynski, Michael; Gibble, Kurt; Gibson, Valerie; Gill, Patrick; Giudice, Gian F.; Goldwin, Jon; Gould, Oliver; Grachov, Oleg; Graham, Peter W.; Grasso, Dario; Griffin, Paul F.; Israelsson, Ulf; Guerlin, Christine; Gündoğan, Mustafa; Gupta, Ratnesh K.; Jeglič, Peter; Jetzer, Philippe; Juzeliūnas, Gediminas; Kaltenbaek, Rainer; Kamenik, Jernej F.; Kehagias, Alex; Bass, Steven; Kirova, Teodora; Kiss-Toth, Marton; Koke, Sebastian; Kolkowitz, Shimon; Kornakov, Georgy; Kovachy, Tim; Krutzik, Markus; Kumar, Mukesh; Kumar, Pradeep; Lämmerzahl, Claus; Bassi, Angelo; Landsberg, Greg; Le Poncin-Lafitte, Christophe; Leibrandt, David R.; Lévèque, Thomas; Lewicki, Marek; Li, Rui; Lipniacka, Anna; Lisdat, Christian; Liu, Mia; Lopez-Gonzalez, J. L.; Battelier, Baptiste; Loriani, Sina; Louko, Jorma; Luciano, Giuseppe Gaetano; Lundblad, Nathan; Maddox, Steve; Mahmoud, M. A.; Maleknejad, Azadeh; March-Russell, John; Massonnet, Didier; McCabe, Christopher; Baynham, Charles F. A.; Meister, Matthias; Mežnaršič, Tadej; Micalizio, Salvatore; Migliaccio, Federica; Millington, Peter; Milosevic, Milan; Mitchell, Jeremiah; Morley, Gavin W.; Müller, Jürgen; Murphy, Eamonn; Beaufils, Quentin; Müstecaplıoğlu, Özgür E.; O’Shea, Val; Oi, Daniel K. L.; Olson, Judith; Pal, Debapriya; Papazoglou, Dimitris G.; Pasatembou, Elizabeth; Paternostro, Mauro; Pawlowski, Krzysztof; Pelucchi, Emanuele; Belić, Aleksandar; Pereira dos Santos, Franck; Peters, Achim; Pikovski, Igor; Pilaftsis, Apostolos; Pinto, Alexandra; Prevedelli, Marco; Puthiya-Veettil, Vishnupriya; Quenby, John; Rafelski, Johann; Rasel, Ernst M.; Bergé, Joel; Ravensbergen, CornelisWe summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.
- ItemSynthetic gravitational horizons in low-dimensional quantum matter(College Park, MD : American Physical Society, 2021) Morice, C.; Moghaddam, A.; Chernyavsky, D.; van Wezel, J.; van den Brink, J.We propose a class of lattice models realizable in a wide range of setups whose low-energy dynamics exactlyreduces to Dirac fields subjected to (1+1)-dimensional [(1+1)D] gravitational backgrounds, including (anti-)deSitter space-time. Wave packets propagating on the lattice exhibit an eternal slowdown for power-law position-dependent hopping integralst(x)∝xγwhenγ 1, signaling the formation of black hole event horizons. Forγ<1 instead the wave packets behave radically different and bounce off the horizon. We show that the eternalslowdown relates to a zero-energy spectral singularity of the lattice model and that the semiclassical wave packetstrajectories coincide with the geodesics on (1+1)D dilaton gravity, paving the way for new and experimentallyfeasible routes to mimic black hole horizons and realize (1+1)D space-times as they appear in certain gravitytheories.
- ItemThermalization by a synthetic horizon(College Park, MD : APS, 2022) Mertens, Lotte; Moghaddam, Ali G.; Chernyavsky, Dmitry; Morice, Corentin; van den Brink, Jeroen; van Wezel, JasperSynthetic horizons in models for quantum matter provide an alternative route to explore fundamental questions of modern gravitational theory. Here we apply these concepts to the problem of emergence of thermal quantum states in the presence of a horizon, by studying ground-state thermalization due to instantaneous horizon creation in a gravitational setting and its condensed matter analog. By a sudden quench to position-dependent hopping amplitudes in a one-dimensional lattice model, we establish the emergence of a thermal state accompanying the formation of a synthetic horizon. The resulting temperature for long chains is shown to be identical to the corresponding Unruh temperature, provided that the postquench Hamiltonian matches the entanglement Hamiltonian of the prequench system. Based on detailed analysis of the outgoing radiation we formulate the conditions required for the synthetic horizon to behave as a purely thermal source, paving a way to explore this interplay of quantum-mechanical and gravitational aspects experimentally.
- ItemTime-lapse gravity and levelling surveys reveal mass loss and ongoing subsidence in the urban subrosion-prone area of Bad Frankenhausen, Germany(Göttingen : Copernicus Publ., 2019) Kobe, Martin; Gabriel, Gerald; Weise, Adelheid; Vogel, DetlefWe present results of sophisticated, high-precision time-lapse gravity monitoring that was conducted over 4 years in Bad Frankenhausen (Germany). To our knowledge, this is the first successful attempt to monitor subrosion-induced mass changes in urban areas with repeated gravimetry. The method provides an approach to estimate the mass of dissolved rocks in the subsurface. Subrosion, i.e. leaching and transfer of soluble rocks, occurs worldwide. Mainly in urban areas, any resulting ground subsidence can cause severe damage, especially if catastrophic events, i.e. collapse sinkholes, occur. Monitoring strategies typically make use of established geodetic methods, such as levelling, and therefore focus on the associated deformation processes. In this study, we combine levelling and highly precise time-lapse gravity observations. Our investigation area is the urban area of Bad Frankenhausen in central Germany, which is prone to subrosion, as many subsidence and sinkhole features on the surface reveal. The city and the surrounding areas are underlain by soluble Permian deposits, which are continuously dissolved by meteoric water and groundwater in a strongly fractured environment. Between 2014 and 2018, a total of 17 high-precision time-lapse gravimetry and 18 levelling campaigns were carried out in quarterly intervals within a local monitoring network. This network covers historical sinkhole areas but also areas that are considered to be stable. Our results reveal ongoing subsidence of up to 30.4 mm a−1 locally, with distinct spatiotemporal variations. Furthermore, we observe a significant time-variable gravity decrease on the order of 8 µGal over 4 years at several measurement points. In the processing workflow, after the application of all required corrections and least squares adjustment to our gravity observations, a significant effect of varying soil water content on the adjusted gravity differences was figured out. Therefore, we place special focus on the correlation of these observations and the correction of the adjusted gravity differences for soil water variations using the Global Land Data Assimilation System (GLDAS) Noah model to separate these effects from subrosion-induced gravity changes. Our investigations demonstrate the feasibility of high-precision time-lapse gravity monitoring in urban areas for sinkhole investigations. Although the observed rates of gravity decrease of 1–2 µGal a−1 are small, we suggest that it is significantly associated with subterranean mass loss due to subrosion processes. We discuss limitations and implications of our approach, as well as give a first quantitative estimation of mass transfer at different depths and for different densities of dissolved rocks.
- ItemThermal effects in gravitational Hartree systems(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2010) Aki, Gonca L.; Dolbeault, Jean; Sparber, ChristofWe consider the non-relativistic Hartree model in the gravitational case, i.e. with attractive Coulomb-Newton interaction. For a given mass $M>0$, we construct stationary states with non-zero temperature T by minimizing the corresponding free energy functional. It is proved that minimizers exist if and only if the temperature of the system is below a certain threshold T^*>0 (possibly infinite), which itself depends on the specific choice of the entropy functional. We also investigate whether the corresponding minimizers are mixed or pure quantum states and characterize a critical temperature T_c in (0, T^*) above which mixed states appear.