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Interferometry with large molecules: exploration of coherence, decoherence and novel beam methods
Arndt, Markus;Hackermüller, Lucia;Reiger, Elisabeth;
Brazilian Journal of Physics , 2005, DOI: 10.1590/S0103-97332005000200004
Abstract: quantum experiments with complex objects are of fundamental interest as they allow to quantitatively trace the quantum-to-classical transition under the influence of various interactions between the quantum object and its environment. we briefly review the present status of matter wave interferometry and decoherence studies with large molecules and focus in particular on the challenges for novel beam methods for molecular quantum optics with clusters, macromolecules or nanocrystals.
Colloquium: Quantum interference of clusters and molecules  [PDF]
Klaus Hornberger,Stefan Gerlich,Philipp Haslinger,Stefan Nimmrichter,Markus Arndt
Physics , 2011, DOI: 10.1103/RevModPhys.84.157
Abstract: We review recent progress and future prospects of matter wave interferometry with complex organic molecules and inorganic clusters. Three variants of a near-field interference effect, based on diffraction by material nanostructures, at optical phase gratings, and at ionizing laser fields are considered. We discuss the theoretical concepts underlying these experiments and the experimental challenges. This includes optimizing interferometer designs as well as understanding the role of decoherence. The high sensitivity of matter wave interference experiments to external perturbations is demonstrated to be useful for accurately measuring internal properties of delocalized nanoparticles. We conclude by investigating the prospects for probing the quantum superposition principle in the limit of high particle mass and complexity.
Real Space Hartree-Fock Configuration Interaction Method For Complex Lateral Quantum Dot Molecules  [PDF]
Ramin M. Abolfath,Pawel Hawrylak
Physics , 2005, DOI: 10.1063/1.2219447
Abstract: We present unrestricted Hartree Fock method coupled with configuration interaction (CI) method (URHF-CI) suitable for the calculation of ground and excited states of large number of electrons localized by complex gate potentials in quasi-two-dimensional quantum dot molecules. The method employs real space finite difference method, incorporating strong magnetic field, for the calculating of single particle states. The Hartree-Fock method is employed for the calculation of direct and exchange interaction contribution to the ground state energy. The effects of correlations are included in energies and directly in the many-particle wavefunctions via configuration interaction (CI) method using a limited set of excitations above the Fermi level. The URHF-CI method and its performance are illustrated on the example of ten electrons confined in a two-dimensional quantum dot molecule.
Aberration cancellation in quantum interferometry  [PDF]
C. Bonato,A. V. Sergienko,B. E. A. Saleh,S. Bonora,P. Villoresi
Physics , 2008, DOI: 10.1103/PhysRevLett.101.233603
Abstract: We report the first experimental demonstration of even-order aberration cancellation in quantum interferometry. The effect is a spatial counterpart of the spectral group velocity dispersion cancellation, which is associated with spectral entanglement. It is manifested in temporal interferometry by virtue of the multi-parameter spatial-spectral entanglement. Spatially-entangled photons, generated by spontaneous parametric down conversion, were subjected to spatial aberrations introduced by a deformable mirror that modulates the wavefront. We show that only odd-order spatial aberrations affect the quality of quantum interference.
Michelson interferometry with quantum noise reduction  [PDF]
Takahisa Mitsui,Kenichiro Aoki
Physics , 2012,
Abstract: A Michelson interferometer with noise reduction to sub-shot noise levels is proposed and realized. Multiple measurements of a single signal beam are taken and the quantum property of light plays an essential role in the principle underlying this interferometry. The method makes use of the coherent state of light and requires only a simple modification to the standard Michelson interferometer. The surface fluctuation spectra of liquids are measured using this method down to a few orders of magnitude below the shot noise level. The spectrum derived from hydrodynamical considerations agrees well with the observed results for water. However, for oil, slight deviations are seen at high frequencies ($\gtrsim1\,$MHz), perhaps indicating its more complex underlying physics. The measurement requires a relatively low light power and a short time, so that it has a wide range of applicability.
`Stückelberg interferometry' with ultracold molecules  [PDF]
M. Mark,T. Kraemer,P. Waldburger,J. Herbig,C. Chin,H. -C. Naegerl,R. Grimm
Physics , 2007, DOI: 10.1103/PhysRevLett.99.113201
Abstract: We report on the realization of a time-domain `St\"uckelberg interferometer', which is based on the internal state structure of ultracold Feshbach molecules. Two subsequent passages through a weak avoided crossing between two different orbital angular momentum states in combination with a variable hold time lead to high-contrast population oscillations. This allows for a precise determination of the energy difference between the two molecular states. We demonstrate a high degree of control over the interferometer dynamics. The interferometric scheme provides new possibilities for precision measurements with ultracold molecules.
Quaternionic quantum interferometry  [PDF]
Asher Peres
Physics , 1996,
Abstract: If scattering amplitudes are ordinary complex numbers (not quaternions) there is a universal algebraic relationship between the six coherent cross sections of any three scatterers (taken singly and pairwise). A violation of this relationship would indicate either that scattering amplitudes are quaternions, or that the superposition principle fails. Some possible experimental tests involve neutron interferometry, K_S-meson regeneration, and low energy proton-proton scattering.
Spatially-controlled complex molecules and their applications  [PDF]
Yuan-Pin Chang,Daniel A. Horke,Sebastian Trippel,Jochen Küpper
Physics , 2015, DOI: 10.1080/0144235X.2015.1077838
Abstract: The understanding of molecular structure and function is at the very heart of the chemical and molecular sciences. Experiments that allow for the creation of structurally pure samples and the investigation of their molecular dynamics and chemical function have developed tremendously over the last few decades, although "there's plenty of room at the bottom" for better control as well as further applications. Here, we describe the use of inhomogeneous electric fields for the manipulation of neutral molecules in the gas-phase, \ie, for the separation of complex molecules according to size, structural isomer, and quantum state. For these complex molecules, all quantum states are strong-field seeking, requiring dynamic fields for their confinement. Current applications of these controlled samples are summarised and interesting future applications discussed.
Quantum Interferometry with Electrons: Outstanding Challenges  [PDF]
Yuval Gefen
Physics , 2002,
Abstract: Recent experiments involving semiconducting quantum dots embedded in Aharonov-Bohm interferometry setups suggest that information concerning the phase of electron wavefunctions can be obtained from transport measurements. Here we review the basics of the theory of electron interferometry, some of the relevant experimental results, and recent theoretical developments attempting to shed light on the outstanding dilemmas.
Diffraction of complex molecules by structures made of light  [PDF]
Olaf Nairz,Bj?rn Brezger,Markus Arndt,Anton Zeilinger
Physics , 2001, DOI: 10.1103/PhysRevLett.87.160401
Abstract: We demonstrate that structures made of light can be used to coherently control the motion of complex molecules. In particular, we show diffraction of the fullerenes C60 and C70 at a thin grating based on a standing light wave. We prove experimentally that the principles of this effect, well known from atom optics, can be successfully extended to massive and large molecules which are internally in a thermodynamic mixed state and which do not exhibit narrow optical resonances. Our results will be important for the observation of quantum interference with even larger and more complex objects.
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