Bose-Einstein Condensates in Magnetic Double Well Potentials PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Bose-Einstein Condensates in Magnetic Double Well Potentials PDF full book. Access full book title Bose-Einstein Condensates in Magnetic Double Well Potentials by Thorsten Schumm. Download full books in PDF and EPUB format.
Author: Thorsten Schumm
Publisher:
ISBN:
Category :
Languages : en
Pages : 189
Get Book Here
Book Description
This thesis presents two realizations of magnetic double well potentials for Bose-Einstein condensates (BECs) on atom chips. One approach utilizes static magnetic traps, created by current carrying micro wires, manipulating the atoms close to the chip surface. As in all other atom chip experiments, cold atom clouds are found to break up to pieces in the vicinity of the trapping structure. A careful study of the underlying magnetic potential could attribute this fragmentation to current deviations, caused by corrugation of the wire edges. To avoid this effect, a new fabrication technique (electron beam lithography, gold evaporation) was employed to create 700nm cross section wires of significantly improved quality. A BEC was created and successfully transferred to the sub-micron structure, generating the double well. The general qualification of the device could be demonstrated by splitting cold thermal atomic clouds. However, numerous technical problems do yet prevent us from performing the experiment with BECs. The second approach pursued in this thesis combines static magnetic traps with oscillating (RF) magnetic fields and realizes a double well in the emerging adiabatic dressed potential. This scheme can be realized far from the chip surface, fragmentation does not occur and Bose-Einstein condensates could be split successfully. We realize a matter wave interferometer by recombining the two clouds in free expansion. The arising interference patterns reveal a narrow distribution of the relative phase, indicating a coherent splitting process. We monitor the phase evolution throughout and after the splitting and control it by deliberately unbalancing the double well.
Author: Thorsten Schumm
Publisher:
ISBN:
Category :
Languages : en
Pages : 189
Get Book Here
Book Description
This thesis presents two realizations of magnetic double well potentials for Bose-Einstein condensates (BECs) on atom chips. One approach utilizes static magnetic traps, created by current carrying micro wires, manipulating the atoms close to the chip surface. As in all other atom chip experiments, cold atom clouds are found to break up to pieces in the vicinity of the trapping structure. A careful study of the underlying magnetic potential could attribute this fragmentation to current deviations, caused by corrugation of the wire edges. To avoid this effect, a new fabrication technique (electron beam lithography, gold evaporation) was employed to create 700nm cross section wires of significantly improved quality. A BEC was created and successfully transferred to the sub-micron structure, generating the double well. The general qualification of the device could be demonstrated by splitting cold thermal atomic clouds. However, numerous technical problems do yet prevent us from performing the experiment with BECs. The second approach pursued in this thesis combines static magnetic traps with oscillating (RF) magnetic fields and realizes a double well in the emerging adiabatic dressed potential. This scheme can be realized far from the chip surface, fragmentation does not occur and Bose-Einstein condensates could be split successfully. We realize a matter wave interferometer by recombining the two clouds in free expansion. The arising interference patterns reveal a narrow distribution of the relative phase, indicating a coherent splitting process. We monitor the phase evolution throughout and after the splitting and control it by deliberately unbalancing the double well.
Author: Tarik Berrada
Publisher: Springer
ISBN: 3319272330
Category : Science
Languages : en
Pages : 244
Get Book Here
Book Description
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: Rudolf Gati
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author: David Ananikian
Publisher:
ISBN: 9781109967159
Category : Bose-Einstein condensation
Languages : en
Pages : 102
Get Book Here
Book Description
At zero temperature the dynamics of the trapped BEC is well described by the Gross-Pitaevskii equation. Our primary goal is to explore the range of validity of a two-mode model in the basis of symmetric and antisymmetric eigenfunctions of the stationary Gross-Pitaevskii equation. In what we call an "improved two-mode model" (I2M), the tunneling coupling energy includes a non-linear term explicitly. We show that when the atom number in each well varies appreciably with time, the nonlinear interaction term produces a temporal change in the tunneling energy or rate. The usefulness of this model is demonstrated by good agreement with recent experimental results for the tunneling oscillation frequency. Especially for larger values of the nonlinear interaction term, the I2M model produces better agreement as compared to the models which have no interaction term in the tunneling energy and fail in the case of large effective coupling constant. In addition, we develop a multimode approach in contrast to Bogoliubov quasiparticle excitation theory. Compared to the I2M model the multimode approach has better agreement with the numerical solution of time-dependent Gross-Pitaevskii equation. A quantum I2M model has been introduced to obtain modified equations of motion for the second quantized version of BEC in the double-well potential. The dynamics of quantum I2M model is essentially governed by the su (2) subalgebra of the full dynamic algebra so (3,2) built on two types of creation and annihilation bose operators. We also extend our results for the case of nonzero temperature in the regime of partial local equilibrium between the condensate and noncondensate atoms deriving equations of motion for the damping oscillations. This approach is based on ZNG theory within the two-mode approximation which treats the noncondensate atoms statically. We analytically elaborate two different regimes: the small oscillation regime about zero imbalance between two wells, and the self-trapping regime about a metastable state with nonzero imbalance.
Author: Sanjaya Lohani
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659273797
Category :
Languages : en
Pages : 88
Get Book Here
Book Description
In the present work the ground state energy of two weakly coupled Bose Einstein condensates separated by double well potential is estimated in three dimensions. By solving three dimensional time independent Gross Pitaevskii equation wave function, density, kinetic energy, potential energy, self energy and total energy of the Bose-Einstein condensates in double well potential have been studied. All these various quantities are also numerically calculated by using Thomas-Fermi Approximation (TFA). It is found that at small number of condensate atoms (N) in the trap, the results obtained from these two methods are quite different but when number of condensate atoms in the trap goes on increasing, the values calculated by using TFA is closer and closer to that obtained from the numerical calculation method. When the value of N is increased, tunneling current in TFA begins to appear and coherent splitting of matter waves starts to be affected. Hence for sufficiently larger value of N, there is "Spontaneous Symmetry Breaking." Further we have numerically calculated the first excited state wave function, density, kinetic energy, potential energy, self energy and total energy.
Author: Slava G Turyshev
Publisher: World Scientific
ISBN: 9814468444
Category : Science
Languages : en
Pages : 764
Get Book Here
Book Description
Space-based laboratory research in fundamental physics is an emerging research discipline that offers great discovery potential and at the same time could drive the development of technological advances which are likely to be important to scientists and technologists in many other different research fields. The articles in this review volume have been contributed by participants of the international workshop “From Quantum to Cosmos: Fundamental Physics Research in Space” held at the Airlie Center in Warrenton, Virginia, USA, on May 21-24, 2006. This unique volume discusses the advances in our understanding of fundamental physics that are anticipated in the near future, and evaluates the discovery potential of a number of recently proposed space-based gravitational experiments. Specific research areas covered include various tests of general relativity and alternative theories, search of physics beyond the Standard Model, investigations of possible violations of the equivalence principle, search for new hypothetical long- and short-range forces, variations of fundamental constants, tests of Lorentz invariance and attempts at unification of the fundamental interactions. The book also encompasses experiments aimed at the discovery of novel phenomena, including dark matter candidates, and studies of dark energy.
Author: Massimo Inguscio
Publisher: Oxford University Press, USA
ISBN: 0198525842
Category : Science
Languages : en
Pages : 349
Get Book Here
Book Description
This book traces the evolution of Atomic Physics from precision spectroscopy to the manipulation of atoms at a billionth of a degree above absolute zero. Quantum worlds can be simulated and fundamental theories, such as General Relativity and Quantum Electrodynamics, can be tested with table-top experiments.
Author: G.M. Tino
Publisher: IOS Press
ISBN: 161499448X
Category : Science
Languages : en
Pages : 807
Get Book Here
Book Description
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: Eleni Sakellari
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Yong-Il Shin
Publisher:
ISBN:
Category :
Languages : en
Pages : 169
Get Book Here
Book Description
(Cont.) Doubly quantized vortices were topologically imprinted in spinor condensates and the stability of the vortex state was investigated. The decay of a doubly-quantized vortex core into two singly-quantized vortex cores was observed using a tomographic imaging technique. The characteristic time scale of the splitting process was found to be longer at higher atom density.
