Ottó Elíasson, Robert Heck, Jens S. Laustsen, Romain Müller, Carrie A. Weidner, Jan J. Arlt, Jacob F. Sherson
Preprint
ArXiv: https://arxiv.org/abs/1912.03079
Abstract: We demonstrate a method to determine the position of single atoms in a three-dimensional optical lattice. Atoms are sparsely loaded from an far-off-resonant optical tweezer into a few vertical planes of a cubic optical lattice positioned near a high-resolution microscope objective. In a single realization of the experiment, we pin the atoms in deep lattices and then acquire multiple fluorescence images with single-site resolution. The objective is translated between images, bringing different vertical planes of the lattice into focus. In this way, we tomographically reconstruct the atom distribution in three dimensions. This opens up the possibility of extending the domain of quantum simulation using quantum gas microscopes from two to three dimensions.
Ottó Elíasson, Robert Heck, Jens S. Laustsen, Mario Napolitano, Romain Müller, Mark G. Bason, Jan J. Arlt, Jacob F. Sherson
Journal of Physics B (2019).
Link: iopscience.iop.org/article/10.1088/1361-6455/ab0bd6
ArXiv: arxiv.org/abs/1811.01798
Abstract: We demonstrate novel implementations of high-precision optical magnetometers which allow for spatially-selective and spatially-resolved in situ measurements using cold atomic clouds. These are realised by using shaped dispersive probe beams combined with spatially-resolved balanced homodyne detection. Two magnetometer sequences are discussed: a vectorial magnetometer, which yields sensitivities two orders of magnitude better compared to a previous realisation and a Larmor magnetometer capable of measuring absolute magnetic fields. We characterise the dependence of single-shot precision on the size of the analysed region for the vectorial magnetometer and provide a lower bound for the measurement precision of magnetic field gradients for the Larmor magnetometer. Finally, we give an outlook on how dynamic trapping potentials combined with selective probing can be used to realise enhanced quantum simulations in quantum gas microscopes.
Robert Heck, Oana Vuculescu, Jens Jakob Sørensen, Jonathan Zoller, Morten G. Andreasen, Mark G. Bason, Poul Ejlertsen, Ottó Elíasson, Pinja Haikka, Jens S. Laustsen, Lærke L. Nielsen, Andrew Mao, Romain Müller, Mario Napolitano, Mads K. Pedersen, Aske R. Thorsen, Carsten Bergenholtz, Tommaso Calarco, Simone Montangero, Jacob F. Sherson
PNAS, vol. 115, no. 48 (2018).
Link: www.pnas.org/content/115/48/E11231
ArXiv: arxiv.org/abs/1709.02230
Abstract: We introduce a novel remote interface to control and optimize the experimental production of Bose-Einstein condensates (BECs) and find improved solutions using two distinct implementations. First, a team of theoreticians employed a Remote version of their dCRAB optimization algorithm (RedCRAB), and second a gamified interface allowed 600 citizen scientists from around the world to participate in real-time optimization. Quantitative studies of player search behavior demonstrated that they collectively engage in a combination of local and global search. This form of adaptive search prevents premature convergence by the explorative behavior of low-performing players while high-performing players locally refine their solutions. In addition, many successful citizen science games have relied on a problem representation that directly engaged the visual or experiential intuition of the players. Here we demonstrate that citizen scientists can also be successful in an entirely abstract problem visualization. This gives encouragement that a much wider range of challenges could potentially be open to gamification in the future.
Mark G Bason, Robert Heck, Mario Napolitano, Ottó Elíasson, Romain Müller, Aske Thorsen, Wen-Zhuo Zhang, Jan J Arlt and Jacob F Sherson.
Journal of Physics B, vol. 51, no. 17 (2018).
Link: http://iopscience.iop.org/article/10.1088/1361-6455/aad447/meta.
ArXiv: arxiv.org/abs/1607.02934
Abstract: We demonstrate how dispersive atom number measurements during evaporative cooling can be used for enhanced determination of the parameter dependence of the transition to a Bose–Einstein condensate (BEC). In this way shot-to-shot fluctuations in initial conditions are detected and the information extracted per experimental realization is increased. We furthermore calibrate in situ images from dispersive probing of a BEC with corresponding absorption images in time-of-flight. This allows for the determination of the transition point in a single experimental realization by applying multiple dispersive measurements. Finally, we explore the continuous probing of several consecutive phase transition crossings using the periodic addition of a focused 'dimple' potential
