Dissertations / Theses on the topic 'Atom chips'
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Treutlein, Philipp. "Coherent manipulation of ultracold atoms on atom chips." Diss., kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/9153/.
Full textSzmuk, Ramon. "Atom chips for metrology." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066089/document.
Full textThis thesis covers two main subjects: the evaluation of the stability of a Trapped Atom Clock on a Chip (TACC) and the expansion of this technology towards creating an atom interferometer on the same chip. The combination of a clock and an interferometer on the same chip constitutes the basis for the realization of atom-based integrated inertial navigation units. Previous work installed the clock operation and discovered, among others, very long coherence times, which allow Ramsey interrogations of up to 5 s, a prerequisite for high stability operation. I present the first thorough evaluation of the clock stability. Together with my predecessor we have demonstrated relative frequency fluctuations of 5.8 10-13 at 1 s integrating down to 6 10-15 at 30,000 s. The second part of this thesis aims to expand the versatility of our atom chip to create an atom interferometer. I have studied various interferometer schemes using microwave dressed potentials and implemented these to the set-up. The first scheme, following work by P. Treutlein et al., involves displacing one of the clock states vertically during a Ramsey clock sequence thereby allowing the measurement of potential gradients by exploiting the differential frequency shift accumulated between the two states. Ramsey fringes where recorded for different durations of the splitting, resulting in a clear signal of the wavepacket separation. The second scheme uses microwave dressing to generate a double well potential in one of the clock states and a single well in the other. Starting in the single well, a π-pulse on the clock transition constitutes the beam splitter and leads to a spatial separation for the same internal state
Trupke, Michael. "Microcavities for atom chips." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491114.
Full textAldous, Matthew Ralph Edward. "Enabling technologies for integrated atom chips." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/418002/.
Full textPollock, Samuel. "Integrated magneto-optical traps for atom chips." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/11271.
Full textRetter, Jocelyn Anna. "Cold atom microtraps above a videotape surface." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270319.
Full textHelsby, Stephen John. "The integration of fibre optics for atom chips." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/63326/.
Full textWhitlock, Shannon, and n/a. "Bose-Einstein condensates on a magnetic film atom chip." Swinburne University of Technology, 2007. http://adt.lib.swin.edu.au./public/adt-VSWT20070613.172308.
Full textZhang, Bo. "Magnetic fields near microstructured surfaces : application to atom chips." Phd thesis, Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2009/2898/.
Full textMikrotechnologische Oberflächen, sogenannte Atomchips, sind eine etablierte Methode zum Speichern und Manipulieren von Atomen geworden. Das hat Anwendungen in der Atom-Interferometrie, Quanteninformationsverarbeitung und Vielteilchensystemen vereinfacht. Magnetische Fallenpotentiale mit beliebigen Geometrien werden durch Atomchips mit miniaturisierten stromführenden Leiterbahnen auf einer Festkörperunterlage realisiert. Atome können bei Temperaturen im $mu$ K oder sogar nK-Bereich in einer solchen Falle gespeichert und gekühlt werden. Allerdings können kalte Atome signifikant durch die Chip-Oberfläche gestört werden, die sich typischerweise auf Raumtemperatur befindet. Die durch thermische Ströme im Chip erzeugten magnetischen Feldfluktuationen können Spin-Flips der Atome induzieren und Verlust, Erwärmung und Dekohärenz zur Folge haben. In dieser Dissertation erweitern wir frühere Arbeiten über durch magnetisches Rauschen induzierte Spin-Flip-Ratenund betrachten kompliziertere Geometrien, wie sie typischerweise auf einem Atom-Chip anzutreffen sind: Geschichtete Strukturen und metallische Leitungen mit endlichem Querschnitt. Wir diskutieren auch einige Aspekte von Aomchips aus Supraleitenden Strukturen die als Mittel zur Unterdrückung magnetischer Feldfluktuationen vorgeschlagen wurden. Die Arbeit beschreibt analytische und numerische Rechnungen von Spin-Flip Raten auf Grundlage magnetischer Greensfunktionen. Für einen Chip mit einem metallischen Top-Layer hängt das magnetische Rauschen hauptsächlich von der Dicke des Layers ab, solange die unteren Layer eine deutlich kleinere Leitfähigkeit haben. Auf Grundlage dieses Ergebnisses werden Skalengesetze für Verlustraten über einem dünnen metallischen Leiter hergeleitet. Eine gute Übereinstimmung mit Experimenten wird in dem Bereich erreicht, wo der Abstand zwischen Atom und Oberfläche in der Größenordnung der Eindringtiefe des Metalls ist. Da in Experimenten metallische Layer immer geätzt werden, um verschiedene stromleitende Bahnen vonenander zu trennen, wurde der Einfluß eines endlichen Querschnittsauf das magnetische Rauschen berücksichtigt. Das lokale Spektrum des magnetischen Feldes in der Nähe einer metallischen Mikrostruktur wurde mit Hilfe von Randintegralen numerisch untersucht. Das magnetische Rauschen hängt signifikant von der Polarisierung über flachen Leiterbahnen mit endlichem Querschnitt ab, im Unterschied zu einem unendlich breiten Leiter. Es wurden auch Korrelationen zwischen mehreren Leitern berücksichtigt. Im letzten Teil werden supraleitende Atomchips betrachtet. Magnetische Fallen, die von supraleitenden Bahnen im Meissner Zustand und im gemischten Zustand sind werden analytisch durch die Methode der konformen Abbildung und numerisch untersucht. Die Eigenschaften der durch supraleitende Bahnen erzeugten Fallen werden erforscht und mit normal leitenden verglichen: Sie verhalten sich qualitativ sehr ähnlich und öffnen einen Weg zur weiteren Miniaturisierung von Fallen, wegen dem Vorteil von geringem magnetischem Rauschen. Wir diskutieren kritische Ströme und Felder für einige Geometrien.
Rushton, Joseph. "A novel magneto-optical trap for integrated atom chips." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/382951/.
Full textRamirez-Martinez, Fernando. "Integration of optical components and magnetic field sources in atom chips." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511289.
Full textHaakh, Harald Richard. "Fluctuation-mediated interactions of atoms and surfaces on a mesoscopic scale." Phd thesis, Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2012/6181/.
Full textThermische und Quantenfluktuationen des elektromagnetischen Nahfelds von Atomen und makroskopischen Körpern spielen eine Schlüsselrolle in der Quantenelektrodynamik (QED), wie etwa beim Lamb-Shift. Sie führen z.B. zur Verschiebung atomarer Energieniveaus, Dispersionswechselwirkungen (Van der Waals-Casimir-Polder-Wechselwirkungen) und Zustandsverbreiterungen (Purcell-Effekt), da das Feld Randbedingungen unterliegt. Mikroelektromechanische Systeme (MEMS) und festkörperbasierte magnetische Fallen für kalte Atome (‘Atom-Chips’) ermöglichen den Zugang zu mesoskopischen Skalen, auf denen solche Effekte mit hoher Genauigkeit beobachtet werden können. Eine Quantenfeldtheorie für Atome (Moleküle) und Photonen wird an Nichtgleichgewichtssituationen angepasst. Atome und Photonen werden durch vollständig quantisierte Felder beschrieben, während die Beschreibung makroskopischer Körper, ähnlich wie im Streuformalismus (scattering approach) der Resonator-QED, durch klassische Streuamplituden erfolgt. In diesem Formalismus wird das Nichtgleich- gewichts-Zweiteilchenpotential diskutiert. Anschließend wird der Einfluss der Materialeigenschaften von normalen Metallen auf das elektromagnetische Oberflächenrauschen, das für magnetische Fallen für kalte Atome auf Atom-Chips und für Quantencomputer-Anwendungen von Bedeutung ist, sowie auf den Beitrag des magnetischen Dipolmoments zum Van der Waals-Casimir-Polder-Potential im thermisch- en Gleichgewicht und in Nichtgleichgewichtssituationen untersucht. In beiden Fällen sind die speziellen Eigenschaften von Supraleitern von besonderem Interesse. Beiträge von Oberflächenmoden, die die Feldfluktuationen im Nahfeld dominieren, werden im Kontext des (partiellen) dynamischen Dressing nach einer raschen Änderung eines Systemparameters sowie für die Casimir-Wechselwirkung zweier metallischer Platten diskutiert, zwischen denen in Nichtgleichgewichtssituationen Abstoßung auftreten kann.
Popp, Manuel André [Verfasser]. "Compact, low-noise current drivers for quantum sensors with atom chips / Manuel André Popp." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1167440722/34.
Full textChuang, Ho-Chiao. "Design, fabrication and characterization of tunable external cavity diode laser and atom trapping chips for atomic physics." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337081.
Full textSchumm, Thorsten. "Bose-Einstein condensates in magnetic double well potentials." Phd thesis, Université Paris Sud - Paris XI, 2006. http://tel.archives-ouvertes.fr/tel-00129501.
Full textLa deuxième approche poursuit dans cette thèse combine des pièges magnétique statique avec un champ (RF) magnétique alternant et génère un double puit dans le potentiel habillé. Car ce schéma peut être réalisé loin de la surface de la puce, la fragmentation n'apparaisse pas et on a pu séparer un CBE en deux. Une interféromètre d'ondes a matière est réalisé en recombinant les deux nuages en expansion libre. La figure d'interférence permet de mesurer la phase relative, on trouve une distribution étroite de cette phase et donc la séparation est cohérente. L'évolution de la phase relative est mesurée pendant et après la séparation et contrôlé par déséquilibrant le double puit.
Lewis, Gareth Neil. "Towards an integrated atom chip." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/66601/.
Full textRiedel, Max. "Multi-particle entanglement on an atom chip." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-126195.
Full textSewell, Rob. "Matter wave interference on an atom chip." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504912.
Full textJones, M. P. A. "Bose Einstein condensation on an atom chip." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270728.
Full textGehr, Roger Peter. "Cavity based high-fidelity and non-destructive single atom detection on an atom chip." Paris 6, 2011. http://www.theses.fr/2011PA066087.
Full textFerreras, Jorge. "One-dimensional Bose gases on an atom chip." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53074/.
Full textNguyen, Thanh Long. "Study of dipole-dipole interaction between Rydberg atoms : toward quantum simulation with Rydberg atoms." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066695/document.
Full textQuantum simulation offers a highly promising way to understand large correlated quantum systems, and many experimental platforms are now being developed. Rydberg atoms are especially appealing thanks to their strong and short-range dipole-dipole interaction. In our setup, we prepare and manipulate ensembles of Rydberg atoms excited from an ultracold atomic cloud magnetically trapped above a superconducting chip. The dynamics of the Rydberg excitation can be controlled through the laser excitation process. The many-body atomic interaction energy spectrum is then directly measured through microwave spectroscopy. This thesis develops a rigorous Monte Carlo model that provides an insight into the excitation process. Using this model, we discuss a possibility to explore quantum simulations of energy transport in a 1D chain of low angular momentum Rydberg atoms. Furthermore, we propose an innovative platform for quantum simulations. It relies on a groundbreaking approach, based on laser-trapped ensemble of extremely long-lived, strongly interacting circular Rydberg atoms. We present intensive numerical results as well as discuss a wide range of problems that can be addressed with the proposed model
Abend, Sven [Verfasser]. "Atom-chip gravimeter with Bose-Einstein condensates / Sven Abend." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1145161693/34.
Full textWhitlock, Shannon. "Bose-Einstein condensates on a magnetic film atom chip." Australasian Digital Thesis Program, 2007. http://adt.lib.swin.edu.au/public/adt-VSWT20070613.172308/index.html.
Full textA thesis submitted for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2007. Typescript. Bibliography: p. 107-118.
Du, Shengwang. "Atom-chip Bose-Einstein condensation in a portable vacuum cell." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3165812.
Full textMatthias, Jonas [Verfasser]. "Magnetic trapping for an atom-chip-based gravimeter / Jonas Matthias." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2020. http://d-nb.info/1221270087/34.
Full textBade, Satyanarayana. "Propagation of atoms in a magnetic waveguide on a chip." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066718/document.
Full textIn this thesis we study the propagation of atoms in a magnetic toroidal waveguide, with the aim of developing an inertial sensor. Here, we present different strategies to create the waveguide on an atom chip for a guided Sagnac atom interferometer. We devised three solutions which can be achieved using the same wire configuration. They use the current modulation technique, from a new point of view, which simultaneously tackles the problem of wire corrugation and spin dependent Majorana atom losses. The effect of the multimode propagation of the atoms in the guide is also quantified in this thesis. Using a simple model, we covered the propagation of noninteracting ultracold and thermal gases. We identified the operating conditions to realize a cold atom interferometer with a large dynamic range essential for applications in inertial navigation. Experimentally, the thesis describes the realisation and characterisation of the cold atom source close to a gold coated substrate, as well as the implementation and the characterisation of the atom detection systems
Ammar, Mahdi. "Design and Study of Microwave Potentials for Interferometry with Thermal Atoms On a Chip." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066532/document.
Full textIn this thesis, we report the theoretical study of an atom interferometer using thermal (i.e. non condensed) atoms trapped on a chip, with reduced mean-field effects. To keep an adequate level of coherence, a high level of symmetry between the arms of such an interferometer is required. To achieve this goal, we describe an experimental protocol based on microwave near-fields created by two coplanar waveguides carrying currents oscillating at different frequencies. This method enables the creation of two symmetrical microwave potentials that depend on the atomic internal state, and allows a state-selective symmetrical splitting of the atoms. We mainly consider two symmetrical configurations to separate the atoms either along the longitudinal axis or along the transverse axis of the static magnetic trap. In the case of a transverse splitting of the atoms, we discuss the advantages of using a custom microtrap that has the same field structure as a standard macroscopic Ioffe Pritchard trap, and we propose a practical design for such a microtrap. In the case of an axial splitting of the atoms, we study some physical factors limiting the ultimate performances of this interferometer such as: the dissymmetry of the microwave potentials, the effect of the fluctuations of static and microwave fields and the stability of the interferometer gravitational signal. We derive a simplified one-dimensional harmonic model to describe the interferometer contrast decay. Finally, we consider the possibility of non-adiabatic atomic splitting and recombination without vibrational heating by designing appropriate trajectories of the trapping-potentials based on the theory of dynamical invariants
Reinhard, Friedemann. "Design and construction of an atomic clock on an atom chip." Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00414386.
Full textSucco, Manuel. "An integrated optical-waveguide chip for measurement of cold-atom clouds." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6394.
Full textBaumgartner, Florian. "Measuring the acceleration of free fall with an atom chip BEC interferometer." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6873.
Full textYuen, Benjamin. "Production and oscillations of a Bose Einstein condensate on an atom chip." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/18833.
Full textBarr, Iain. "Investigating the dynamics of a Bose Einstein condensate on an atom chip." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/26226.
Full textYan, Wenhua. "Design of a magnetic guide for rotation sensing by on chip atom interferometry." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066548.
Full textThis manuscript present the design and realization of an experimental setup for the development of a cold atom interferometer using 87Rb atoms guided on an atom chip, the final goal being the realization of an inertial sensor for rotation measurements. We have therefore study theoretically the magnetic confinement of these atoms in a circular guide. Such a study allowed us to identify the main challenges linked to the atomic wave packet propagation along a stable circular orbit in a magnetic guide, namely: the roughness of the guiding potential, the magnetic potential defects associated to the pattern of the micro wires used to produce this potential, and the Majorana losses. In this thesis we propose original solutions to these questions based on preliminary studies and on the results of our calculations. From the experimental point of view, we have assembled a new cold atom experiment with the main feature of being compact and therefore transportable for in situ measurement of rotations. We have along this work put together an efficient ultra high vacuum system, developed a compact optical bench containing the laser sources for cooling and trapping, a Bragg laser for the atom interferometer, as well as all the needed electronics to control the experiment
Singh, Mandip. "A magnetic lattice and macroscopic entanglement of a BEC on an atom chip." Swinburne Research Bank, 2008. http://hdl.handle.net/1959.3/55142.
Full textThesis submitted for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2008. Typescript. Bibliography: p. 143-158.
Ziltz, Austin R. "Ultracold rubidium and potassium system for atom chip-based microwave and RF potentials." W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539624008.
Full textHommelhoff, Peter. "Bose-Einstein-Kondensate in Mikrochip-Fallen." Phd thesis, [S.l.] : [s.n.], 2002. http://edoc.ub.uni-muenchen.de/archive/00000702.
Full textLaudat, Théo. "Spontaneous spin squeezing in a spinor Bose-Einstein condensate trapped on an atom chip." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEO014/document.
Full textIn this manuscript, we present an experimental study of spin squeezing in a spinor Bose-Einstein condensate of $^{87}Rb$, arising from a non-linear interaction originating from collisions between the two internal states $|F=1, m_F=-1>$ and $|F=2, m_F=1>$ of the $5^2S_{1/2}$ manifold. The atoms are cooled down in a magneto-optical trap and magnetically trapped thanks to our atom-chip which acts as a top wall for our vacuum cell. The chip is also used to emit the radio-frequency field that perform the evaporative cooling leading to Bose-Einstein condensation, and the microwave field used to coherently transfer the atoms from one internal state to another.The atomic ensemble in a coherent superposition is well described by the so-called textit{one-axis-twisting} Hamiltonian that contains a term quadratic in the $z$-component of the spin vector $S_z$. the strength of this non-linear interaction, initially very weak, depends on the intra- and inter-state s-wave scattering lengths, and can be greatly enhanced by reducing the wave-function spatial overlap between the two states. We therefore place the system in a configuration (high atom number and cigar-shaped trap) for which the two states experience spontaneous relative spatial separation and recombination phases. The impact of this spatial dynamics on the mean field interaction and coherence of the system is experimentally analyzed through the study of the contrast and central frequency of a Ramsey interferometer.Theoretically, when the two states are separated, the spin noise distribution evolves from a uniform circular distribution defined by the quantum projection noise, to an elliptic one whose small axis is smaller than the standard quantum limit, under the action of the $S_z^2$ interaction. This is verified experimentally by performing the tomography of the atomic state, when the two internal modes recombine. A squeezing parameter $xi^2=-1.3 pm 0.4$ dB is reached for 5000 atoms and a 90% contrast. The study of the different instability sources highlights the atomic-density-dependent losses as the main limitation for both the noise reduction and the contrast of the interferometer.This work has been initiated in the context of quantum metrology and represents a step towards the production of spin squeezed states enabling the realization of atom interferometers working below the standard quantum limit. It also addresses the fundamental question of coherence of spinor Bose-Einstein condensates undergoing many elastic and inelastic collisions
Haas, Florian. "Creation of entangled states of a set of atoms in an optical cavity." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-00968861.
Full textGollasch, Carsten Olaf. "An electrostatic micro actuator for aligning and tuning an optical cavity on an atom chip." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446614.
Full textAlibert, Julien. "Une nouvelle source pour l'interférométrie atomique avec un condensat de Bose-Einstein double espèce." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30350/document.
Full textAtom interferometry has shown its interest for high precision measurements, such as inertial sensors, tests of fundamental physics or fundamental constant measurements. A way to improve sensitivity of such device is to reduce speed dispersion of the atomic cloud. The use of ultra-cold atoms allows increasing the interogation time of atoms and the spatial separation between the interferometer arms. The building of a new atom interferometer with separated arms is ongoing in the laboratory "Collisions Agrégats et Réactivité" at Toulouse. This new setup must meet two objectives. One aim of its conception is to study and develop a new kind of double species Bose-Einstein condensate (B.E.C.) source for atom interferometry with rubidium 87 and 85. This B.E.C. source relies on atom chip technology to cool down and manipulate atoms. This technology is compact and low power consuming, therefore suitable for transportable applications in space. A second aim is to use this interferometer to fix new boundary on the experimental value of atom neutrality thanks to the scalar Aharonov-Bohm effect. In this manuscript I start by exposing and justifying technical choices made for the design of the double isotope B.E.C. source. Then I present the first experimental results compared with numerical simulations and theoretical explanations. During the first laser cooling stage we produce a cloud including 4 × 10^10 rubidium atoms of both isotopes (87 and 85) at 10 µK. This operation can be repeated every second. Following the laser cooling 8×10^9 atoms are loaded into a millimeter sized magnetic trap. Various experiments were performed to characterize the trap. Studies of the trap frequency and depth revealed the limitations of this first prototype. However these theoretical and experimental developments led to design and future implementation of a new generation of micro-chip in our apparatus
Deutsch, Christian. "Trapped atom clock on a chip : identical spin rotation effects in an ultracold trapped atomic clock." Paris 6, 2011. http://www.theses.fr/2011PA066742.
Full textHermann, Avigliano Carla. "Towards deterministic preparation of single Rydberg atoms and applications to quantum information processing." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066351/document.
Full textRydberg atoms and superconducting cavities are remarkable tools for the exploration of basic quantum phenomena and quantum information processing. These giant atoms are blessed with unique properties. They undergo a strong distance-Dependent dipole-Dipole interaction that gives rise to the dipole blockade mechanism: in the Van der Waals regime, this energy shift scales as n11, where n is the principal quantum number. If we shine an excitation laser tuned at the frequency of the isolated atomic transition on an atomic cloud, we expect to excite at most one atom within a blockade volume of ⇠ 8(μm)3. We have set up an experiment to prepare deterministically one Rydberg atom. It uses a small cloud of ground-State Rubidium 87 atoms, magnetically trapped on a superconducting atom chip at 4 K, and laser-Excited to the Rydberg states. The dipole blockade effect is sensitive to the line broadening due to the stray electric fields. Once an atom has been excited to our target state HH 60S1/2↵, we explore the narrow millimeter-Wave transitions between Rydberg states in order to assess these stray fields . With a gold-Coated front surface for the chip, we observe as other groups large field gradients due to slowly deposited Rubidium atoms. We circumvent this problem by coating the chip with a metallic Rubidium layer. This way the gradients are reduced by an order of magnitude. This improvement allows us to observe extremely high coherence times, in the millisecond range, for Rydberg atoms near a superconducting atom-Chip. Theoretically, we present a simple scheme for the fast and efficient generation of quantum superpositions of two coherent fields with different classical amplitudes in a cavity. It relies on the simultaneous interaction of two two-Level atoms with the field. Their final detection with a high probability in the proper state projects the field onto the desired mesoscopic field state superposition (MFSS). We show that the scheme is notably more efficient than those using a single atom. This work is done in the context of cavity QED, where the two-Level systems are circular Rydberg atoms whose lifetime may reach milliseconds, interacting with the field of a superconducting microwave cavity. But this scheme is also highly relevant for the thriving field of circuit-QED. In both contexts, it may lead to interesting experimental studies of decoherence at the quantum-Classical boundary
Forchel, Dirk, and Rainer G. Spallek. "VLSI-Realisierungen für ATM: eine Übersicht." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-98769.
Full textDupont-Nivet, Matthieu. "Vers un accéléromètre atomique sur puce." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLO007/document.
Full textIn this manuscript we report the theoretical and experimental developments, in progress at TRT, aiming at the realisation of a cold atom accelerometer. This accelerometer uses an ultra-cold non-degenerated gas which is trapped in the vicinity of an atom chip during the whole interrogation sequence.We describe an interrogation protocol allowing the sensor to be sensitive to acceleration. This protocol uses a Ramsey sequence with a spatial separation of the two interferometer states. The signal and the contrast of this interferometer are derived and the use of shortcut to adiabadicity is considered to enable fast splitting and merging of the two states. We also describe a design of the accelerometer on an atom chip. This design use two dressed microwave potentials, one for each of the two interferometer states.We described the atom cooling experiment built during this thesis. Atoms of rubidium 87 have been cooled to Bose-Einstein condensation in state $left|2,2right>$. A stimulated Raman adiabatic passage protocol using microwave fields, allows to transfer an atomic cloud (condensed or thermal) to the state $left|2,1right>$. With this atomic source the contrast of the Ramsey fringes as a function of the symmetry between the interferometer traps have been measured. The measured contrast falling time is in good agreement with the theoretical prediction for the interferometer contrast
Christandl, Katharina. "Advancing neutral atom quantum computing studies of one-dimensional and two-dimensional optical lattices on a chip /." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1123263229.
Full textTitle from first page of PDF file. Document formatted into pages; contains xxiii, 261 p.; also includes graphics. Includes bibliographical references (p. 256-261). Available online via OhioLINK's ETD Center
Lewoczko-Adamczyk, Wojciech. "Bose-Einstein condensation in microgravity." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15970.
Full textRecently, cooling, trapping and manipulation of neutral atoms and ions has become an especially active field of quantum physics. The main motivation for the cooling is to reduce motional effects in high precision measurements including spectroscopy, atomic clocks and matter interferometry. The spectrum of applications of these quantum devices cover a broad area from geodesy, through metrology up to addressing the fundamental questions in physics, as for instance testing the Einstein’s equivalence principle. However, the unprecedented precision of the quantum sensors is limited in terrestial laboratories. Freezing atomic motion can be nowadays put to the limit at which gravity becomes a major perturbation in a system. Gravity can significantly affect and disturb the trapping potential. This limits the use of ultra-shallow traps for low energetic particles. Moreover, free particles are accelerated by gravitational force, which substantially limits the observation time. Targeting the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of a Bose-Einstein condensate (BEC) experiment under microgravity conditions at the drop tower in Bremen. Special challenges in the construction of the experimental setup are posed by a low volume of the drop capsule as well as critical decelerations up to 50g during recapture at the bottom of the tower. All mechanical and electronic components were thus been designed with stringent demands on miniaturization and mechanical stability. This work reports on the observation of a BEC released from an ultra-shallow magnetic potential and freely expanding for one second. Both, the low trapping frequency and long expansion time are not achievable in any earthbound laboratory. This unprecedented time of free evolution leads to new possibilities for the study of BEC-coherence. It can also be applied to enhance the sensitivity of inertial quantum sensors based on ultra-cold matter waves.
Forchel, Dirk, and Rainer G. Spallek. "VLSI-Realisierungen für ATM: eine Übersicht." Technische Universität Dresden, 1997. https://tud.qucosa.de/id/qucosa%3A26201.
Full textSahelgozin, Maral [Verfasser]. "Design and construction of a transportable quantum gravimeter and realization of an atom-chip magnetic trap / Maral Sahelgozin." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1190283417/34.
Full textHohmann, Leander. "Using optical fibre cavities to create multi-atom entanglement by quantum zeno dynamics." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066053/document.
Full textIn this thesis, we show how an optical microcavity setup can create multiparticle entanglement in an ensemble of neutral atoms by means of quantum Zeno dynamics (QZD).Our setup combines an atom chip with a fibre Fabry-Perot (FFP) resonator and allows us to load an ensemble of Rb87 atoms into a single node of an intracavity dipole trap, coupling the atoms strongly and identically to the cavity light field which enables us to perform a quantum non-destructive measurement of their collective state.We realise QZD by modifying the dynamics of the collective state (encoded in atomic hyperfine states addressed with MW radiation) by means of frequent cavity measurements at optical frequency. This QZD is shown to create multiparticle entanglement in a fast and deterministic scheme. To analyse the created states, we reconstruct the symmetric part of the atomic density matrix from 2d measurements of the ensemble's Husimi Q-distribution. We give a time-resolved account of the creation of states with at least 3-11 entangled atoms and fidelity of up to 0.37 with respect to a W state of 36 atoms. Studying the influence of measurement strength and experimental imperfections, we show that our experiments are well described by simple models with no free parameters.This thesis also presents work towards improved FFP cavities. We discuss the problem of frequency splitting of polarisation eigenmodes in cavities made from two fibres microfabricated with a CO2 laser. We show that this effect depends on the symmetry of the microfabricated structures and demonstrate that it can be controlled both at the level of fabrication and when assembling a cavity