Renpeng Fang

Effects of non-idealities and quantization of the center of mass motion on symmetric and asymmetric collective states in a collective state atomic interferometer

We investigate the behavior of an ensemble of non-interacting, identical atoms excited by a laser. In general, the -th atom sees a Rabi frequency , an initial position dependent laser phase , and a motion induced Doppler shift of . When or is distinct for each atom, the system evolves into a superposition of intercoupled states, of which there are symmetric and asymmetric collective states. For a collective state atomic interferometer (COSAIN), we recently proposed, it is important to understand the behavior of all the collective states under various conditions. In this paper, we show how to formulate the properties of these states under various non-idealities, and use this formulation to understand the dynamics thereof. We also consider the effect of treating the center of mass degree of freedom of the atoms quantum mechanically on the description of the collective states, illustrating that it is indeed possible to construct a generalized collective state, as needed for the COSAIN, when each atom is assumed to be in a localized wave packet. The analysis presented in this paper is important for understanding the dynamics of the COSAIN, and will help advance the analysis and optimization of spin squeezing in the presence of practically unavoidable non-idealities as well as in the domain where the center of mass motion of the atoms is quantized.

N -atom collective-state atomic interferometer with ultrahigh Compton frequency and ultrashort de Broglie wavelength, with N reduction in fringe width

We describe a collective state atomic interferometer (COSAIN) with the signal fringe as a function of phase-difference or rotation narrowed by

An N-atom Collective State Atomic Clock with Root-N Fold Increase in Effective Frequency and Root-N Fold Reduction in Fringe Width

\sqrt{N}

Extreme Phase-Amplification under Direct Detection of Atomic States for Heisenberg Limited Sensitivity in an Atomic Interferometer Employing Schroedinger Cat States

compared to a conventional interferometer -

Generation of arbitrary lithographic patterns using Bose-Einstein-condensate interferometry

N

Generalized Collective States and Their Role in a Collective State Atomic Interferometer and Atomic Clock

being the number of atoms - without entanglement. This effect arises from the interferences among collective states, and is a manifestation of interference at a Compton frequency of ten nonillion Hz, or a de Broglie wavelength of ten attometer, for

High-Compton-frequency, parity-independent, mesoscopic Schrödinger-cat-state atom interferometer with Heisenberg-limited sensitivity

N=10^6

Increasing Sensitivity of an Atom Interferometer to the Heisenberg Limit using Enhanced Quantum Noise

and

Ultra-high compton frequency, parity independent, mesoscopic schroedinger cat atom interferometer with heisenberg limited sensitivity

v = 300 m/s

Enhancing Sensitivity of an Atom Interferometer to the Heisenberg Limit using Increased Quantum Noise

. The population of the collective state of interest is detected by a null measurement scheme, in which an event corresponding to detection of zero photons corresponds to the system being in that particular collective state. The signal is detected by collecting fluorescence through stimulated Raman scattering of Stokes photons, which are emitted predominantly against the direction of the probe beam, for a high enough resonant optical density. The sensitivity of the ideal COSAIN is found to be given by the standard quantum limit. However, when detection efficiency and collection efficiency are taken into account, the detection scheme of the COSAIN increases the quantum efficiency of detection significantly in comparison to a typical conventional Raman atomic interferometer employing fluorescence detection, yielding a net improvement in stability by as much as a factor of