Quantum computing with magnetic atoms in optical lattices of reduced periodicity

We investigate the feasibility of combining Raman optical lattices with a quantum computing architecture based on lattice-confined magnetically interacting neutral atoms. A particular advantage of the standing Raman field lattices comes from reduced interatomic separations leading to increased interatomic interactions and improved multi-qubit gate performance. Specifically, we analyze a $J=3/2$ Zeeman system placed in $_{+}-\sigma_{-}$ Raman fields which exhibit $\lambda /4$ periodicity. We find that the resulting CNOT gate operations times are in the order of millisecond. We also investigate motional and magnetic-field induced decoherences specific to the proposed architecture

Differential Light Shift Cancellation in a Magnetic-Field-Insensitive Transition of 87^{87}Rb

We demonstrate near-complete cancellation of the differential light shift of a two-photon magnetic-field-insensitive microwave hyperfine (clock) transition in $^{87}$Rb atoms trapped in an optical lattice. Up to $95(2)$ of the differential light shift is canceled while maintaining magnetic-field insensitivity. This technique should have applications in quantum information and frequency metrology.Comment: 5 pages, 4 figure

Colloquium: Physics of optical lattice clocks

Recently invented and demonstrated, optical lattice clocks hold great promise for improving the precision of modern timekeeping. These clocks aim at the 10^-18 fractional accuracy, which translates into a clock that would neither lose or gain a fraction of a second over an estimated age of the Universe. In these clocks, millions of atoms are trapped and interrogated simultaneously, dramatically improving clock stability. Here we discuss the principles of operation of these clocks and, in particular, a novel concept of "magic" trapping of atoms in optical lattices. We also highlight recently proposed microwave lattice clocks and several applications that employ the optical lattice clocks as a platform for precision measurements and quantum information processing.Comment: 18 pages, 15 figure

Quantum network of neutral atom clocks

We propose a protocol for creating a fully entangled GHZ-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use of the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum operations involving all atoms in the ensemble. The necessary entanglement between distant ensembles is mediated by single-photon quantum channels and collectively enhanced light-matter couplings. These techniques can be used to create the recently proposed quantum clock network based on neutral atom optical clocks. We specifically analyze a possible realization of this scheme using neutral Yb ensembles.Comment: 13 pages, 11 figure

Post-Wick theorems for symbolic manipulation of second-quantized expressions in atomic many-body perturbation theory

Manipulating expressions in many-body perturbation theory becomes unwieldily with increasing order of the perturbation theory. Here I derive a set of theorems for efficient simplification of such expressions. The derived rules are specifically designed for implementing with symbolic algebra tools. As an illustration, we count the numbers of Brueckner-Goldstone diagrams in the first several orders of many-body perturbation theory for matrix elements between two states of a mono-valent system.Comment: J. Phys. B. (in press); Mathematica packages available from http://wolfweb.unr.edu/homepage/andrei/WWW-tap/mathematica.htm

Reevaluation of Stark-induced transition polarizabilities in cesium

Extracting electroweak observables from experiments on atomic parity violation (APV) using the Stark interference technique requires accurate knowledge of transition polarizabilities. In cesium, the focus of our paper, the $6S_{1/2}\rightarrow{7S_{1/2}}$ APV amplitude is deduced from the measured ratio of the APV amplitude to the vector transition polarizability, $\beta$. This ratio was measured with a $0.35\%$ uncertainty by the Boulder group [Science 275, 1759 (1997)]. Currently, there is a sizable discrepancy in different determinations of $\beta$ critically limiting the interpretation of the APV measurement. The most recent value [Phys. Rev. Lett. 123, 073002 (2019)] of $\beta=27.139(42)\, \mathrm{a.u.}$ was deduced from a semi-empirical sum-over-state determination of the scalar transition polarizability $\alpha$ and the measured $\alpha/\beta$ ratio [Phys. Rev. A 55, 1007 (1997)]. This value of $\beta$, however, differs by $\sim 0.7\%$ or $2.8\sigma$ from the previous determination of $\beta=26.957(51)$ by [Phys. Rev. A 62, 052101 (2000)] based on the measured ratio $M1/\beta$ of the magnetic-dipole $6S_{1/2}\rightarrow{7S_{1/2}}$ matrix element to $\beta$. Here, we revise the determination of $\beta$ by [Phys. Rev. Lett. 123, 073002 (2019)], using a more consistent and more theoretically complete treatment of contributions from the excited intermediate states in the sum-over-state $\alpha/\beta$ method. Our result of $\beta=26.887(38)\, \mathrm{a.u.}$ resolves the tension between the $\alpha/\beta$ and $M1/\beta$ approaches. We recommend the value of $\beta=26.912(30)$ obtained by averaging our result and that of [Phys. Rev. A 62, 052101 (2000)].Comment: 9 pages, 2 figures v2: Reference added, small cosmetic changes to the tex

Nuclear-spin-dependent corrections to the transition polarizability in cesium

The Stark-interference technique is commonly used to amplify the feeble parity-violating signal in atomic experiments. As a result, interpretation of these experiments in terms of electroweak observables requires knowledge of the Stark-induced $E1$ transition amplitudes or, equivalently, transition polarizabilities. While the literature assumes that these transition polarizabilities do not depend on the nuclear spin, here we prove the contrary. The nuclear spin dependence arises due to hyperfine mixing of atomic states and requires a third-order perturbation theory (one hyperfine interaction and two electric-dipole interactions) treatment. We demonstrate that the so far neglected {\em tensor} contribution appears in the transition polarizability and present numerical results for the nuclear-spin-dependent corrections to the $6S_{1/2}\rightarrow{7S_{1/2}}$ transition polarizability in $^{133}$Cs. We investigate the effect of these corrections to transition polarizabilities on the extraction of the $^{133}$Cs anapole moment from the Boulder experiment [Science 275, 1759 (1997)]. We also consider their effect on the extraction of the ratio between the scalar and vector transition polarizabilities from the measurements [Phys. Rev. A 55, 2 (1997)]. While the corrections are minor at the current level of experimental accuracy, our analysis provides a framework for future experiments.Comment: 11 pages, 1 figur

AC Stark shift of the Cs microwave atomic clock transitions

We analyze the AC Stark shift of the Cs microwave atomic clock transition theoretically and experimentally. Theoretical and experimental data are in a good agreement with each other. Results indicate the absence of a magic wavelength at which there would be no differential shift of the clock states having zero projections of the total angular momentum