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Quantum mechanics in the general quantum systems (V): Hamiltonian eigenvalues

We derive out a complete series expression of Hamiltonian eigenvalues without any approximation and cut in the general quantum systems based on Wang's formal framework \cite{wang1}. In particular, we then propose a calculating approach of eigenvalues of arbitrary Hamiltonian via solving an algebra equation satisfied by a kernal function, which involves the contributions from all order perturbations. In order to verify the validity of our expressions and reveal the power of our approach, we calculate the ground state energy of a quartic anharmonic oscillator and have obtained good enough results comparing with the known one.

quant-ph↗

Quantum Mechanics in the general quantum systems (VI): exact series solution of stationary Schrödinger's equation

We obtain a complete series solution of stationary Schrödinger's equation in the general quantum systems. It is exact in the sense that any approximation means is not used, or that the whole corrections or contributions from all order perturbations are involved if the perturbation concept is introduced. Furthermore, the useful forms of our exact solution and a new expression the complete Green operator are given out. As a universal and analytical solution, it is helpful for the theoretical derivations and practical calculations in quantum theory.

quant-ph↗

Going from Classical to Quantum Description of Bound Charged Particles Part 1: Basic Concepts and Assertions

In this paper we analyze again a transition from the classical to quantum description of bound charged particles, which involves a substantial modification of the structure of their electromagnetic (EM) fields related to the well-known fact that bound micro-particles do not radiate in sta-tionary energy states. We show that a simple exclusion of the radiative component of EM field produced by bound particles leads to a violation of the energy-momentum conservation law, if the non-radiative EM field is left unmodified. In order to restore the energy-momentum conservation, we make a closer look at the interaction of two hypothetical classical charges with the prohibited radiation component of their EM field and bring the appropriate modifications in the structure of their bound EM field and, accordingly, in the Hamilton function of this system. In comparison with the common Hamilton function for the one-body problem, the electric interaction energy is multiplied by the Lorentz factor of orbiting charged particle, and its rest mass m is replaced by an effective rest mass parameter, which includes the interaction EM energy. We introduce, as a novel postulate, these replacements into the Dirac equation for the bound electron and show that the solution of the modified Dirac Coulomb equation gives the same gross and fine structure of energy levels, as the one furnished by the conventional approach, for hydrogen-like atoms. The correction to spin-spin splitting of 1S state of hydrogen and heavier atoms is much smaller than nuclear structure contribution and can be ignored. However, as discussed in the part 2 of this paper, our approach does induce corrections to the energy levels at the scale of hyperfine interactions, which at once remove a number of long-standing discrepancies between theory and experiment in the atomic physics.

physics.atom-ph↗

Optical vortex filtering for the detection of Electromagnetically Induced Transparency

We report the realization of an optical filter based on an optical vortex mask designed to exclusively detect a weak coherent laser field in the presence of much stronger spatially-overlapping field. We demonstrate the performance of such an optical vortex filter to eliminate the strong control field and detect only a weak optical field's transmission under the conditions of electromagnetically induced transparency. The attractive feature of such filter is its insensitivity to optical field frequencies and polarizations, which makes it applicable for a wide range of coherent processes.

physics.optics↗

Recent Interests on Positron, Positronium and Antimatters

A brief survey is made to highlight the recent interests in positron, positronium and antimatter physics. Positron is the first antiparticle observed which was predicted by Dirac. Positronium is itself its antiparticle and bi-positronium molecule is recently observed in laboratory which was predicted by Wheeler. The simplest antiatom i.e. antihydrogen is observed in the laboratory and the process to achieve the stable confinement of antihydrogen within the trap are in progress to test the standard model.

physics.pop-ph↗

Single Photon Atomic Sorting: Isotope Separation with Maxwell's Demon

Isotope separation is one of the grand challenges of modern society and holds great potential for basic science, medicine, energy, and defense. We consider here a new and general approach to isotope separation. The method is based on an irreversible change of the mass-to-magnetic moment ratio of a particular isotope in an atomic beam, followed by a magnetic multipole whose gradients deflect and guide the atoms. The underlying mechanism is a reduction of the entropy of the beam by the information of a single-scattered photon for each atom that is separated. We numerically simulate isotope separation for a range of examples, including lithium, for which we describe the experimental setup we are currently constructing. Simulations of other examples demonstrate this technique's general applicability to almost the entire periodic table. We show that the efficiency of the process is only limited by the available laser power, since one photon on average enables the separation of one atom. The practical importance of the proposed method is that large-scale isotope separation should be possible, using ordinary inexpensive magnets and the existing technologies of supersonic beams and lasers.

physics.atom-ph↗

Quantum rotator: some examples in modern spirit

Rotation of the nucleus and rotation of the electronic cloud of the atom/ion were considered. It was shown that these rotations are not practically possible. Rotation of the cloud of delocalized electrons and ionic core of a fullerene molecule and these of the ring of a nanotube were discussed. It was shown that the rotation of the cloud of delocalized electrons of a fullerene molecule is possible and it goes in a quantum way when temperature is essentially lower than 40 K. Rotation of the ion core of a fullerene molecule is possible in a classical way only. The same should be said about rotations in the ring of a nanotube.

physics.chem-ph↗

String-inspired ultraviolet/infrared mixing and preliminary evidence of a violation of the de Broglie relation for nonrelativistic neutrons

We advocate a novel perspective on the phenomenology of a framework with spacetime noncommutativity which is of established relevance for string theory. Our analysis applies to cases in which the noncommutativity parameters are arranged according to the criteria of "light-like noncommutativity" and ultraviolet supersymmetry is assumed, so that the implications of the characteristic mechanism of ultraviolet/infrared mixing are relatively soft. We also observe that an analogous case of soft ultraviolet-infrared mixing is present in a previously-proposed Loop-quantum-gravity-inspired description of quantum spacetime. And we show that soft ultraviolet-infrared mixing produces an anomaly for the nonrelativistic de Broglie relation $λv = h/m$, with correction term governed by a single (but particle-dependent) parameter $χ$. We test this hypothesis by comparing a determination of the fine structure constant that relies on the de Broglie relation for nonrelativistic neutrons to other independent determinations of the fine structure constant, and we obtain an estimate of $χ$ that differs from 0 with four-standard-deviation significance.

hep-th↗

EIT-based Vector Magnetometry in Linear Polarized Light

We develop a generalized principle of EIT vector magnetometry based on high-contrast EIT-resonances and the symmetry of atom-light interaction in the linearly polarized bichromatic fields. Operation of such vector magnetometer on the D1 line of 87Rb has been demonstrated. The proposed compass-magnetometer has an increased immunity to shifts produced by quadratic Zeeman and ac-Stark effects, as well as by atom-buffer gas and atom-atom collisions. In our proof-of-principle experiment the detected sensitivity to magnetic field orientation is 10^{-3} deg/Hz^{1/2}, which is limited by laser intensity fluctuations, light polarization quality, and the magnitude of the magnetic field.

physics.atom-ph↗

Velocity selective trapping of atoms in a frequency-modulated standing laser wave

The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field may suppress packet splitting for some atoms having specific velocities in a narrow range. These atoms remain localized in a small space for a long time. We propose that in a real experiment with cold atomic gas this effect may decrease the velocity distribution of atoms (the field traps the atoms with such specific velocities while all other atoms leave the field)

physics.atom-ph↗

Momentum distribution of atoms in one-dimensional Raman cooling with arbitrary coherent population transfer

We derive an exact and analytical form for the cold-atom momentum distribution after a large number of one-dimensional (1D) Raman cooling cycles has been applied. Our result shows that one can select pulse profiles and lengths rather freely in order to obtain efficient cooling. Our approach takes into account optical pumping (resonant excitation followed by spontaneous emission) as an intergral part of the process, and it is noted that it does not affect the final momentum distribution. Thus subrecoil cooling is possible in general, and not just for carefully selected combinations of pulse forms and durations.

physics.atom-ph↗

Hartree-Fock calculations for the photoionisation of helium and helium-like ions in neutron star magnetic fields

We derive the photoionisation cross section in dipole approximation for many-electron atoms and ions for neutron star magnetic field strengths in the range of 10^7 to 10^9 T. Both bound and continuum states are treated in adiabatic approximation in a self-consistent way. Bound states are calculated by solving the Hartree-Fock-Roothaan equations using finite-element and B-spline techniques while the continuum orbital is calculated by direct integration of the Hartree-Fock equations in the mean-field potential of the remaining bound orbitals. We take into account mass and photon density in the neutron star's atmosphere, finite nuclear mass as well as thermal occupation of the levels. The data may be of importance for the quantitative interpretation of observed x-ray spectra that originate from the thermal emission of isolated neutron stars. They can serve as input for modeling neutron star atmospheres as regards chemical composition, magnetic field strength, temperature, and redshift. Our main focus in this paper lies on helium and helium-like oxygen. These two-electron systems are simple enough to calculate all possible transitions when limiting the quantum numbers and should show all the basic structures and behaviour of other two-electron systems up to iron.

physics.atom-ph↗

Signature of multi-channel interference in high-order harmonic generation from N2 driven by intense mid-infrared pulses

We investigate the multi-electron dynamics in high-order harmonic generation (HHG) from N2 molecules. Clear spectral minima are observed in the cutoff region at all three mid-infrared wavelengths (i.e., 1300, 1400 and 1500 nm) chosen in our experiment. It is found that the positions of the spectral minima do not depend on the alignment angles of molecules. In addition, the spectral minima shift almost linearly with the increasing laser intensity at all three wavelengths, which provides a strong evidence on the dynamic multi-channel interference origin of these minima. The advantages of observation of dynamic multi-channel interference based on HHG driven by long wavelength lasers are discussed.

physics.atom-ph↗

Application of the Space-Time Method to Stimulated Raman Adiabatic Passage on the Simple Harmonic Oscillator

The space-time method is applied to a model system-the Simple Harmonic Oscillator in a laser field to simulate the Stimulated Raman Adiabatic Passage (STIRAP) process. The Space-Time method is a computational theory first introduced by Weatherford et. al. to solve Time-Dependent Systems with one boundary value and applied to electron spin system with invariant Hamiltonian [Journal of Molecular Structure {\bf 592} 47]. The implementation in the present work provides an efficient and general way to solve the Time-Dependent Schr{ö}dinger Equation and can be applied to multi-state systems. The algorithm for simulating the Simple Harmonic Oscillator STIRAP can be applied to solve STIRAP problems for complex systems.

physics.comp-ph↗

Phase-Shift Plateaus in the Sagnac Effect for Matter Waves

We simulate ultracold Sagnac atom interferometers using quantum-mechanical matter wavepackets, e.g. Bose-Einstein condensates, that counter-propagate within a rotating ring-trap. We find that the accumulation of the relative phase difference between wavepackets, i.e. the matter wave Sagnac effect, is manifested as discrete phase jumps. These plateaus result from three effects; that the atoms should be initially trapped at rest with respect to the rotating frame, that they counter-propagate with the same group velocities in the rotating frame, and that the imaging is performed in the rotating frame. We show that the plateaus persist in the presence of nonlinear atom-atom interactions, and in atoms undergoing various rotations, and thus will occur during matter wavepacket experiments. We also introduce the simplest possible Sagnac atom interferometry scheme which relies on wavepacket dispersion around a ring-trap.

physics.atom-ph↗

Light transmission through and its complete stoppage in an ultra slow wave optical medium

Light Wave transmission -- its compression, amplification, and the optical energy storage -- in an Ultra Slow Wave Medium (USWM) is studied analytically. Our phenomenological treatment is based entirely on the continuity equation for the optical energy flux, and the well known distribution-product property of Dirac delta-function. The results so obtained provide a clear understanding of some recent experiments on light transmission and its complete stoppage in an USWM. Keywords : Ultra slow light, stopped light, slow wave medium, EIT.

physics.optics↗

The Electron Capture $^{163}$Ho Experiment ECHo

The determination of the absolute scale of the neutrino masses is one of the most challenging questions in particle physics. Different approaches are followed to achieve a sensitivity on neutrino masses in the sub-eV range. Among them, experiments exploring the beta decay and electron capture processes of suitable nuclides can provide necessary information on the electron neutrino mass value. In this talk we present the Electron Capture 163-Ho experiment ECHo, which aims to investigate the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured energy spectrum following the electron capture process of 163-Ho. A high precision and high statistics spectrum will be measured by means of low temperature magnetic calorimeter arrays. We present preliminary results obtained with a first prototype of single channel detectors as well as the participating groups and their on-going developments.

physics.ins-det↗