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Author : Ying-Ju Wang
Publisher :
ISBN 13 :
Total Pages : 202 pages
Book Rating : 4.:/5 (624 download)
Download or read book An On-chip Atom Interferometer Using a Bose-Einstein Condensate written by Ying-Ju Wang and published by . This book was released on 2005 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Tarik Berrada
Publisher : Springer
ISBN 13 : 3319272330
Total Pages : 244 pages
Book Rating : 4.3/5 (192 download)
Download or read book Interferometry with Interacting Bose-Einstein Condensates in a Double-Well Potential written by Tarik Berrada and published by Springer. This book was released on 2015-12-17 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis demonstrates a full Mach–Zehnder interferometer with interacting Bose–Einstein condensates confined on an atom chip. It relies on the coherent manipulation of atoms trapped in a magnetic double-well potential, for which the author developed a novel type of beam splitter. Particle-wave duality enables the construction of interferometers for matter waves, which complement optical interferometers in precision measurement devices, both for technological applications and fundamental tests. This requires the development of atom-optics analogues to beam splitters, phase shifters and recombiners. Particle interactions in the Bose–Einstein condensate lead to a nonlinearity, absent in photon optics. This is exploited to generate a non-classical state with reduced atom-number fluctuations inside the interferometer. This state is then used to study the interaction-induced dephasing of the quantum superposition. The resulting coherence times are found to be a factor of three longer than expected for coherent states, highlighting the potential of entanglement as a resource for quantum-enhanced metrology.
Author : Boris Décamps
Publisher :
ISBN 13 :
Total Pages : 304 pages
Book Rating : 4.:/5 (1 download)
Download or read book Atom Interferometry written by Boris Décamps and published by . This book was released on 2016 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis's first part describes the realization of three experiments using an atom interferometer operated with a lithium supersonic beam. The second part presents the development of a new BEC interferometer designed to test matter neutrality. The first three experiments rely on the interactions of lithium atom with different electromagnetic fields. A time dependent electric potential difference was used to produce phase modulation of both interferometer arms at different frequencies, leading to homodyne and heterodyne detection of atom waves. A geometric phase of light (the Pancharatnam phase) was successfully transferred to our interferometer signal during Bragg diffraction, enlarging the atom optics toolbox for phase control in an atom interferometer. Finally, a focused laser beam was used to measure accurately the value of one lithium tune-out wavelength (for which its dynamic polarizability is zero). The new BEC interferometer was designed to measure a possible non-zero electric charge of rubidium isotopes 85Rb and 87Rb with enhanced sensitivity to the electron-proton charge difference and neutron neutrality. This setup relies on a large spatial separation between the two interferometer arms in a fountain configuration aiming at a cycle time of 5s. These features required particular design work both on the atomic source (atom-chip) and the diffraction process (Large Momentum Transfer). The technical choices on the vacuum chambers, laser system and magnetic sources are described and characterized. Finally, the up-to-date cold-atom source performances is shown and compared to our expectations.
Author : Julia Pahl
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (142 download)
Download or read book Atom Interferometric Experiments with Bose-Einstein Condensates in Microgravity written by Julia Pahl and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Englische Version: Light-pulse atom interferometry (AI) is an important tool for high precision measurements in the fields of inertial sensing or fundamental physics. Especially in combination with ultra-cold atomic sources and operation in microgravity, high sensitivities are expected that are necessary for the search for violations of the weak equivalence principle. QUANTUS-2 is a mobile atom interferometer operating at the ZARM drop tower in Bremen. With its high-flux, atom chip-based atomic rubidium source, it serves as a pathfinder for future space missions, examining key technologies like the generation of Bose-Einstein condensates (BECs), implementation of delta-kick collimation or application of various AI geometries. In this thesis, a potassium diode laser system has been built to complete the preordained functionality of dual-species operation. Based on the design of the rubidium laser system with micro-integrated laser diode modules and compact electronics, it successfully passed the qualification tests. In a proof of principle measurement, a potassium magneto-optical trap could be generated to prove the system's capability of trapping atoms. With rubidium, open Ramsey type interferometers and Mach-Zehnder interferometers (MZIs) were examined on ground and in over 155 drops in microgravity. The combination of variably delta-kicked collimated BECs and AI in microgravity revealed a new technique to determine the magnetic lens duration for optimal collimation. Asymmetric MZIs with interferometry times of 2T > 1s have successfully been demonstrated. Gravimetric examinations on ground with MZIs and by an additional levitation technique have been performed to determine the local gravitational acceleration g. The examined key technologies are fundamental necessities that have to be considered to pave the way for future space missions.
Author : Christian Groß
Publisher : Springer Science & Business Media
ISBN 13 : 3642256368
Total Pages : 123 pages
Book Rating : 4.6/5 (422 download)
Download or read book Spin Squeezing and Non-linear Atom Interferometry with Bose-Einstein Condensates written by Christian Groß and published by Springer Science & Business Media. This book was released on 2012-01-13 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interferometry, the most precise measurement technique known today, exploits the wave-like nature of the atoms or photons in the interferometer. As expected from the laws of quantum mechanics, the granular, particle-like features of the individually independent atoms or photons are responsible for the precision limit, the shot noise limit. However this “classical” bound is not fundamental and it is the aim of quantum metrology to overcome it by employing entanglement among the particles. This work reports on the realization of spin-squeezed states suitable for atom interferometry. Spin squeezing was generated on the basis of motional and spin degrees of freedom, whereby the latter allowed the implementation of a full interferometer with quantum-enhanced precision.
Author : Billy Ian Robertson
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)
Download or read book High Contrast Measurements with a Bose-Einstein Condensate Atom Interferometer written by Billy Ian Robertson and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom interferometry is a next-generation technique of precision measurement that can vastly outperform its optical analogue. These devices utilise the wave nature of atoms to make interferometric measurements of, for example, gravitational and magnetic fields, inertial effects, and the fine-structure constant. The main focus of this thesis is the creation of a general purpose atom interferometer in free space.We create a Bose-Einstein condensate of ~105 87Rb atoms in a crossed-optical dipole trap. The atomic wave function is coherently manipulated using highly tuned pulses comprising off-resonant light that form our atom-optical elements. These atom optics are analogous to the beam splitters and mirrors in an optical interferometer. By controlling the timing and amplitude of the pulses we demonstrate the ability to excite specific momentum states with high efficiency. The tuned atom optics allows for the construction of an atom interferometer in free space. From this we can measure the recoil velocity of an 87Rb atom and calculate the value of the fine structure constant. We also demonstrate the measurement of magnetic field gradients using atom interferometry. A second method of data readout is also demonstrated, known as contrast interferometry.This increases the rate at which information is obtained and decreases the measurement duration from a few hours to a few minutes.Within the vacuum chamber we also have a copper ring which form the basis of an AC coupled ring trap for atoms. The long term goal is to use this as a waveguide for atom interferometry and, whilst not the main focus of this thesis, we present some proof-of-principle type data demonstrating the ring trap. In addition we show the first Kapitza-Dirac splitting of a BEC within the waveguide which forms the first part of a guided atom interferometer.
Author : Bretislav Friedrich
Publisher : Springer Nature
ISBN 13 : 3030639630
Total Pages : 639 pages
Book Rating : 4.0/5 (36 download)
Download or read book Molecular Beams in Physics and Chemistry written by Bretislav Friedrich and published by Springer Nature. This book was released on 2021-06-19 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Open Access book gives a comprehensive account of both the history and current achievements of molecular beam research. In 1919, Otto Stern launched the revolutionary molecular beam technique. This technique made it possible to send atoms and molecules with well-defined momentum through vacuum and to measure with high accuracy the deflections they underwent when acted upon by transversal forces. These measurements revealed unforeseen quantum properties of nuclei, atoms, and molecules that became the basis for our current understanding of quantum matter. This volume shows that many key areas of modern physics and chemistry owe their beginnings to the seminal molecular beam work of Otto Stern and his school. Written by internationally recognized experts, the contributions in this volume will help experienced researchers and incoming graduate students alike to keep abreast of current developments in molecular beam research as well as to appreciate the history and evolution of this powerful method and the knowledge it reveals.
Author : Jakob Reichel
Publisher : John Wiley & Sons
ISBN 13 : 3527643923
Total Pages : 412 pages
Book Rating : 4.5/5 (276 download)
Download or read book Atom Chips written by Jakob Reichel and published by John Wiley & Sons. This book was released on 2011-08-24 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This stimulating discussion of a rapidly developing field is divided into two parts. The first features tutorials in textbook style providing self-contained introductions to the various areas relevant to atom chip research. Part II contains research reviews that provide an integrated account of the current state in an active area of research where atom chips are employed, and explore possible routes of future progress. Depending on the subject, the length of the review and the relative weight of the 'review' and 'outlook' parts vary, since the authors include their own personal view and style in their accounts.
Author : G.M. Tino
Publisher : IOS Press
ISBN 13 : 161499448X
Total Pages : 807 pages
Book Rating : 4.6/5 (149 download)
Download or read book Atom Interferometry written by G.M. Tino and published by IOS Press. This book was released on 2014-10-16 with total page 807 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since atom interferometers were first realized about 20 years ago, atom interferometry has had many applications in basic and applied science, and has been used to measure gravity acceleration, rotations and fundamental physical quantities with unprecedented precision. Future applications range from tests of general relativity to the development of next-generation inertial navigation systems. This book presents the lectures and notes from the Enrico Fermi school "Atom Interferometry", held in Varenna, Italy, in July 2013. The aim of the school was to cover basic experimental and theoretical aspects and to provide an updated review of current activities in the field as well as main achievements, open issues and future prospects. Topics covered include theoretical background and experimental schemes for atom interferometry; ultracold atoms and atom optics; comparison of atom, light, electron and neutron interferometers and their applications; high precision measurements with atom interferometry and their application to tests of fundamental physics, gravitation, inertial measurements and geophysics; measurement of fundamental constants; interferometry with quantum degenerate gases; matter wave interferometry beyond classical limits; large area interferometers; atom interferometry on chips; and interferometry with molecules. The book will be a valuable source of reference for students, newcomers and experts in the field of atom interferometry.
Author : Ebubechukwu Odidika Ilo-Okeke
Publisher :
ISBN 13 :
Total Pages : 226 pages
Book Rating : 4.:/5 (828 download)
Download or read book Guided-wave Atom Interferometers with Bose-Einstein Condensate written by Ebubechukwu Odidika Ilo-Okeke and published by . This book was released on 2012 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: An atom interferometer is a sensitive device that has potential for many useful applications. Atoms are sensitive to electromagnetic fields due to their electric and magnetic moments and their mass allows them to be deflected in a gravitational field, thereby making them attractive for measuring inertial forces. The narrow momentum distribution of Bose-Einstein condensate (BEC) is a great asset in realizing portable atom interferometers. An example is a guided-wave atom interferometer that uses a confining potential to guide the motion of the condensate. Despite the promise of guided-wave atom interferometry with BEC, spatial phase and phase diffusion limit the contrast of the interference fringes. The control of these phases is required for successful development of a BEC-based guided-wave atom interferometer. This thesis analyses the guided-wave atom interferometer, where an atomic BEC cloud at the center of a confining potential is split into two clouds that move along different arms of the interferometer. The clouds accumulate relative phase due to the environment, spatially inhomogeneous trapping potential and atom-atom interactions within the condensate. At the end of the interferometric cycle, the clouds are recombined producing a cloud at rest and moving clouds. The number of atoms in the clouds that emerge depends on the relative phase accumulated by the clouds during propagation. This is investigated by deriving an expression for the probability of finding any given number of atoms in the clouds that emerge after recombination. Characteristic features like mean, standard deviation and cross-correlation function of the probability density distribution are calculated and the contrast of the interference fringes is optimized. This thesis found that optimum contrast is achieved through the control of total population of atoms in the condensate, trap frequencies, s-wave scattering length, and the duration of the interferometric cycle.
Author : Florian Baumgärtner
Publisher : Sudwestdeutscher Verlag Fur Hochschulschriften AG
ISBN 13 : 9783838131900
Total Pages : 132 pages
Book Rating : 4.1/5 (319 download)
Download or read book Atom Chip BEC Interferometer written by Florian Baumgärtner and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2012 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Bose-Einstein condensate (BEC) interferometer on an atom chip is capable of making an absolute force measurement. The author demonstrates this by making an absolute measurement of the gravitational acceleration g. Two interferometer arms are implemented by splitting a BEC into two symmetric wells using radio-frequency (rf) adiabatic potentials. The independent control of the rf currents running through the chip surface allows to change the polarisation of the rf field and hence the orientation of the double well potential. Tilting of the system with respect to the horizontal introduces an energy difference and the relative phase between the BECs starts to evolve. After moving the atoms back to their initial position and overlapping the clouds in free fall the resulting phase exhibits in the interference pattern. In order to derive a number for g from experimental results a detailed analysis and understanding of the interferometer scheme is essential.
Author : Rudra Prasad Kafle
Publisher :
ISBN 13 :
Total Pages : 490 pages
Book Rating : 4.:/5 (83 download)
Download or read book Theoretical Study of Bose-Einstein Condensate-Based Atom Michelson Interferometers written by Rudra Prasad Kafle and published by . This book was released on 2012 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Atom interferometers and gyroscopes are highly sensitive atom-optical devices which are capable to measure inertial, gravitational, electric, and magnetic fields and to sense rotations. Theoretically, the signal-to-noise ratio of atomic gyroscopes is about a hundred billion times more than that of their optical counterparts for the same particle flux and the enclosed area. Ultra cold atoms from a Bose-Einstein condensate (BEC) can easily be controlled and coherently manipulated on small chips by laser pulses. Atom-optical devices will therefore play a significant role in fundamental research, precision measurements, and navigation systems. In BEC-based atom interferometers, a BEC in a trap is split by using laser pulses, the split clouds are allowed to evolve, they are reflected, and then recombined by laser pulses to observe interference. The split clouds accumulate spatial phase because of the trap and the nonlinearity caused by atom-atom interactions. A velocity mismatch due to reflection laser pulses also introduces a phase gradient across each cloud. These factors contribute to spatial relative phase between the clouds at recombination, causing the loss of contrast of the interference fringes. The main objective of this dissertation is to study the dynamics of a split condensate in atom Michelson interferometers, investigate the effect of trap frequencies, nonlinearity, and the velocity mismatch on the contrast, and to obtain the best theoretical limit of performance in terms of the experimental parameters: trap frequencies, number of atoms, and the velocity imparted to the clouds by the splitting laser pulses.
Author : Ofir Garcia-Salazar
Publisher :
ISBN 13 :
Total Pages : 488 pages
Book Rating : 4.X/5 (3 download)
Download or read book Bose-Einstein-condensate Interferometer with Macroscopic Arm Separation written by Ofir Garcia-Salazar and published by . This book was released on 2007 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Gauthier Guillaume
Publisher : Springer Nature
ISBN 13 : 3030549674
Total Pages : 177 pages
Book Rating : 4.0/5 (35 download)
Download or read book Transport and Turbulence in Quasi-Uniform and Versatile Bose-Einstein Condensates written by Gauthier Guillaume and published by Springer Nature. This book was released on 2020-09-26 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advancing the experimental study of superfluids relies on increasingly sophisticated techniques. We develop and demonstrate the loading of Bose-Einstein condensates (BECs) into nearly arbitrary trapping potentials, with a resolution improved by a factor of seven when compared to reported systems. These advanced control techniques have since been adopted by several cold atoms labs around the world. How this BEC system was used to study 2D superfluid dynamics is described. In particular, negative temperature vortex states in a two-dimensional quantum fluid were observed. These states were first predicted by Lars Onsager 70 years ago and have significance to 2D turbulence in quantum and classical fluids, long-range interacting systems, and defect dynamics in high-energy physics. These experiments have established dilute-gas BECs as the prototypical system for the experimental study of point vortices and their nonequilibrium dynamics. We also developed a new approach to superfluid circuitry based on classical acoustic circuits, demonstrating its conceptual and quantitative superiority over previous lumped-element models. This has established foundational principles of superfluid circuitry that will impact the design of future transport experiments and new generation quantum devices, such as atomtronics circuits and superfluid sensors.
Author : Paul Anthony Altin
Publisher :
ISBN 13 :
Total Pages : 342 pages
Book Rating : 4.:/5 (845 download)
Download or read book The Role of Interactions in Atom Interferometry with Bose-Condensed Atoms written by Paul Anthony Altin and published by . This book was released on 2012 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, atom interferometry has become established as an indispensable tool in both fundamental and applied physics. With present state-of-the-art devices based on thermal atoms reaching limits imposed by the momentum spread of the initial atomic wavepacket, it seems natural to ask whether colder sources such as Bose-Einstein condensates may prove beneficial in advancing the precision of interferometric measurements. The thesis at hand aims to inform this question, specifically by examining the role played by atomic interactions in interferometers based on Bose-condensed atoms. Interactions can have both advantageous and deleterious consequences in the context of atom interferometry. They provide a means to control the momentum width of the condensate, and facilitate the generation of nonclassical squeezed states which may enhance the phase sensitivity beyond the shot noise limit. Conversely, the condensate self-interaction causes mean-field shifts, multimode excitations and phase diffusion which can erode both the precision and the accuracy of an interferometric measurement. The question of when and in which systems the detrimental effects of interactions outweigh the advantages of using Bose-Einstein condensates is an important one, and warrants investigation. This thesis presents experimental studies into the role of interactions in both internal- and external-state atom interferometers. As a foundation for these investigations, we describe the design and construction of an apparatus for creating Bose-Einstein condensates of the two stable rubidium isotopes in an optical trap. By sympathetic cooling with a rubidium-87 reservoir, we are able to produce condensates of rubidium-85 in which the interactions may be adjusted by means of a magnetic Feshbach resonance. The tunability afforded by the Feshbach resonance is used to study inelastic losses in ultracold rubidium-85 clouds, as well as the effect of interactions on condensate stability and on the ground state of dual-species mixtures. In particular, we offer new experimental data on the dynamics of collapsing condensates with attractive interactions, over which some controversy has existed since the first experiments more than a decade ago. Good agreement is found between the measured collapse times and a simple mean-field model. Proceeding to interferometry, we present results from Ramsey interferometers operating on the clock transition of rubidium-87 Bose-Einstein condensates. In free-space operation with Raman beamsplitters, we demonstrate projection-noise-limited performance, an important prerequisite for the realisation of squeezing-enhanced sensitivity. Using large condensates of up to 106 atoms and microwave coupling, we study the effect of interactions on the Ramsey fringe contrast. The dominant source of decoherence is found to be spatial dynamics driven by the difference in interparticle interaction strengths, which are analysed using the spin-echo technique and numerical simulations of the Gross-Pitaevskii equation. Finally, we turn our attention to external-state interferometry, implementing a Mach-Zehnder gravimeter using Bragg transitions in a freely falling rubidium-87 condensate. Large-momentum-transfer beamsplitters composed of higher-order Bragg diffraction and Bloch oscillations are used to increase the accumulated phase and thus the sensitivity of the interferometer. The role of interactions in this system is examined, and we canvass methods for achieving further increases in sensitivity. -- provided by Candidate.
Author : Daniel Doering
Publisher :
ISBN 13 :
Total Pages : 280 pages
Book Rating : 4.:/5 (953 download)
Download or read book Interferometry and Precision Measurements with Bose-condensed Atoms written by Daniel Doering and published by . This book was released on 2011 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bose-Einstein condensates are coherent matter waves, produced by cooling gaseous atomic clouds to ultra-low temperatures. For applications in atom interferometry and precision measurements, Bose-condensed sources present an intriguing alternative to thermal atoms. Although the current sensitivity achievable with interferometers using coherent atoms is not comparable to thermal beam machines (mainly due to the lower flux), there are promising ways to utilise the potential of Bose-condensed sources for atom interferometry. Among those is the low momentum width of Bose-Einstein condensates, which can generally be well controlled and is advantageous for increased interferometric sensitivities by implementing large momentum transfer beam splitters. As part of this thesis, experimental and theoretical investigations are presented to investigate the potential of Bose-Einstein condensates for such applications. We shall present the quantum projection noise limited performance of a Ramsey interferometer operating on the atomic clock transition of a freely expanding cloud of Bose-condensed rubidium 87 atoms. The results include Ramsey fringes of high visibility, not measurably affected by atomic interaction-induced dephasing effects. The achievement and detection of the quantum projection noise limit rely critically on the precision and accuracy of both the imaging setup and the coupling scheme in the interferometric beam splitters. The stabilisation of the beam splitters via an optical Sagnac interferometer is the basis for the quantum projection noise limited performance of the interferometer presented. For an increase of bandwidth and flux in atom interferometric measurements, it is advantageous to use a continuous atomic beam. A truly continuous coherent atom source has not been realised to date, and we present results on a pumping mechanism in this thesis, as a decisive step towards a continuous atom laser. By the investigation of different momentum resonances, we find that the pumping scheme relies on a Raman superradiance-like process. Finally, the thesis demonstrates two interaction measurements in rubidium. The strong mean field interactions due to the high densities in Bose-Einstein condensates are used to probe the potential of a rubidium 87 condensate with an atom laser. The measurement allows a determination of the scattering length between the two atomic states involved. In addition to this two-body scattering scheme, we present a measurement of three-body loss coefficients, extracted from loss curves in rubidium 85 Bose-Einstein condensates. The measurement provides new upper bounds on the three-body loss coefficients at the scattering lengths considered.
Author : Merle Cornelius
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)
Download or read book Atom Interferometry with Picokelvin Ensembles in Microgravity written by Merle Cornelius and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom interferometry enables precision measurements with outstanding sensitivities in a broad field of applications, ranging from fundamental physics to applications in geodesy or navigation. The development of robust and mobile devices paves the way for future satellite missions, e.g. striving for improved spaceborne gravimetry or a precision test of the universality of free fall. The sensitivity of an atom interferometer scales quadratically with the interrogation time. Consequentially, exceptional sensitivities can be reached for interferometry with free evolving ensembles on time scales of several seconds, achievable by operating on a microgravity platform. Such long interrogation times necessarily require ensembles with ultra-low expansion rates, making collimated Bose-Einstein condensates (BEC) the ideal input states. Therefore a method called magnetic lensing is used to narrow the momentum distribution. Together with the very good coherence properties of BECs, this reduces uncertainties in the interferometric measurement and enables high-fidelity beam splitter processes like Bragg diffraction. Within the scope of this thesis, a novel matter-wave lens system is presented to lower the internal kinetic energy of a BEC to the picokelvin regime, which is then used to perform interferometric measurements in microgravity. This is achieved with the QUANTUS-2 apparatus, a high-flux rubidium BEC machine based on atom chip technology, which operates at the drop tower in Bremen. Exploiting the excitation of a quadrupole mode in combination with a magnetic lens attains three-dimensional collimation of the BEC. With this technique, an unprecedented residual kinetic energy of $ sfrac{3}{2}k_B cdot38 ,$pK is achieved, where the ensemble is observed after an interrogation time of 2$ ,$s with a high signal-to-noise ratio. Upgrading the experiment to realize single and double Bragg diffraction enables the first demonstration of a double Bragg-based interferometer in microgravity with a retro-reflection setup. The symmetric splitting achieved with the double Bragg process doubles the enclosed interferometer area and reduces systematic effects compared to single diffraction techniques. A complete characterization is performed to optimize the beam splitting process and verify the feasibility of atom chip setups for interferometric measurements. The potential of magnetically lensed BECs for interferometric measurements is investigated by probing the spatial coherence. To this end, a novel application of shear interferometry is developed to investigate the divergence of the magnetically lensed ensemble in analogy to an optical shear plate. Based on the interferometry pattern, the imperfections of the magnetic lens potential are studied, and the lens strength is optimized. Shear interferometry even enables the spatially resolved determination of the BEC's velocity field based on the interferometry pattern. Consequentially, the internal kinetic energy can be deduced from a single absorption image. Especially compact, ground-based atom interferometers can profit from this characterization method since extended times of flight are not required. This shear interferometry represents a versatile tool to study BEC dynamics independently of the application in matter-wave optics. The first demonstration of interferometry with picokelvin atomic ensembles and the tools developed in this work provide the basis to realize atom interferometry on extended time scales of several seconds. This will ultimately enable future space missions to employ cold atom interferometry at unrivalled levels of precision.
