Bose-Einstein Condensates in Radio-frequency-dressed Potentials on an Atom Chip PDF Download
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Author: Johannes Joris Pieter van Es.
Publisher:
ISBN: 9789057761867
Category :
Languages : en
Pages : 131
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Author: Johannes Joris Pieter van Es.
Publisher:
ISBN: 9789057761867
Category :
Languages : en
Pages : 131
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Book Description
Author: Sebastian Hofferberth
Publisher:
ISBN:
Category :
Languages : en
Pages : 165
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Book Description
Author: Tarik Berrada
Publisher: Springer
ISBN: 3319272330
Category : Science
Languages : en
Pages : 244
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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: Thorsten Schumm
Publisher:
ISBN:
Category :
Languages : en
Pages : 189
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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: Jakob Reichel
Publisher: John Wiley & Sons
ISBN: 3527643923
Category : Science
Languages : en
Pages : 412
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Book Description
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: Tim Langen
Publisher: Springer
ISBN: 3319185640
Category : Science
Languages : en
Pages : 154
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Book Description
This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.
Author: Marcius H. T. Extravour
Publisher:
ISBN: 9780494609507
Category :
Languages : en
Pages : 190
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Book Description
Ultra-cold dilute gases of neutral atoms are attractive candidates for creating controlled mesoscopic quantum systems. In particular, quantum degenerate gases of bosonic and fermionic atoms can be used to model the correlated many-body behaviour of Bose and Fermi condensed matter systems, and to study matter wave interference and coherence.This thesis describes the experimental realization and manipulation of Bose-Einstein condensates (BECs) of 87Rb and degenerate Fermi gases (DFGs) of 40K using static and dynamic magnetic atom chip traps. Atom chips are versatile modern tools used to manipulate atomic gases. The chips consist of micrometre-scale conductors supported by a planar insulating substrate, and can be used to create confining potentials for neutral atoms tens or hundreds of micrometres from the chip surface. We demonstrate for the first time that a DFG can be produced via sympathetic cooling with a BEC using a simple single-vacuum-chamber apparatus. The large 40 K-87Rb collision rate afforded by the strongly confining atom chip potential permits rapid cooling of 40K to quantum degeneracy via sympathetic cooling with 87Rb. By studying 40K-87Rb cross-thermalization as a function of temperature, we observe the Ramsauer-Townsend reduction in the 40K-87Rb elastic scattering cross-section. We achieve DFG temperatures as low as T ≈ 0:1TF, and observe Fermi pressure in the time-of-flight expansion of the gas.This thesis also describes the radio-frequency (RF) manipulation of trapped atoms to create dressed state double-well potentials for BEC and DFG. We demonstrate for the first time that RF-dressed potentials are species-selective, permitting the formation of simultaneous 87Rb double-well and 40K single-well potentials using a 40K-87Rb mixture. We also develop tools to measure fluctuations of the relative atom number and relative phase of a dynamically split 87Rb BEC. In particular, we observe atom number fluctuations at the shot-noise level using time-of-flight absorption imaging. These measurement tools lay the foundation for future investigations of number squeezing and matter wave coherence in BEC and DFG systems.
Author: Marcius H. T. Extavour
Publisher:
ISBN: 9780494609507
Category :
Languages : en
Pages : 0
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Book Description
Ultra-cold dilute gases of neutral atoms are attractive candidates for creating controlled mesoscopic quantum systems. In particular, quantum degenerate gases of bosonic and fermionic atoms can be used to model the correlated many-body behaviour of Bose and Fermi condensed matter systems, and to study matter wave interference and coherence. This thesis describes the experimental realization and manipulation of Bose-Einstein condensates (BECs) of 87Rb and degenerate Fermi gases (DFGs) of 40K using static and dynamic magnetic atom chip traps. Atom chips are versatile modern tools used to manipulate atomic gases. The chips consist of micrometre-scale conductors supported by a planar insulating substrate, and can be used to create confining potentials for neutral atoms tens or hundreds of micrometres from the chip surface. We demonstrate for the first time that a DFG can be produced via sympathetic cooling with a BEC using a simple single-vacuum-chamber apparatus. The large 40 K-87Rb collision rate afforded by the strongly confining atom chip potential permits rapid cooling of 40K to quantum degeneracy via sympathetic cooling with 87Rb. By studying 40K-87Rb cross-thermalization as a function of temperature, we observe the Ramsauer-Townsend reduction in the 40K-87Rb elastic scattering cross-section. We achieve DFG temperatures as low as T & ap; 0:1TF, and observe Fermi pressure in the time-of-flight expansion of the gas. This thesis also describes the radio-frequency (RF) manipulation of trapped atoms to create dressed state double-well potentials for BEC and DFG. We demonstrate for the first time that RF-dressed potentials are species-selective, permitting the formation of simultaneous 87Rb double-well and 40K single-well potentials using a 40K-87Rb mixture. We also develop tools to measure fluctuations of the relative atom number and relative phase of a dynamically split 87Rb BEC. In particular, we observe atom number fluctuations at the shot-noise level using time-of-flight absorption imaging. These measurement tools lay the foundation for future investigations of number squeezing and matter wave coherence in BEC and DFG systems.
Author: Christian Groß
Publisher: Springer Science & Business Media
ISBN: 3642256376
Category : Science
Languages : en
Pages : 123
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Book Description
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: Edem Tsikata
Publisher:
ISBN:
Category :
Languages : en
Pages : 108
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Book Description
