Ultra-high sensitivity magnetic field and magnetization measurements with an atomic magnetometer

We describe an ultra-sensitive atomic magnetometer using optically-pumped potassium atoms operating in spin-exchange relaxation free (SERF) regime. We demonstrate magnetic field sensitivity of 160 aT/Hz$^{1/2}$ in a gradiometer arrangement with a measurement volume of 0.45 cm$^3$ and energy resolution per unit time of $44 \hbar$. As an example of a new application enabled by such a magnetometer we describe measurements of weak remnant rock magnetization as a function of temperature with a sensitivity on the order of 10$^{-10}$ emu/cm$^3$/Hz$^{1/2}$ and temperatures up to 420$^\circ$C

Nonlinear magneto-optical rotation of frequency-modulated light resonant with a low-J transition

A low-light-power theory of nonlinear magneto-optical rotation of frequency-modulated light resonant with a J=1->J'=0 transition is presented. The theory is developed for a Doppler-free transition, and then modified to account for Doppler broadening and velocity mixing due to collisions. The results of the theory are shown to be in qualitative agreement with experimental data obtained for the rubidium D1 line.Comment: 11 pages, 5 figures, v.2 edited for clarit

P- and T-violating Schiff moment of the Mercury nucleus

The Schiff moment of the $^{199}$Hg nucleus was calculated using finite range P- and T-violating weak nucleon-nucleon interaction. Effects of the core polarization were considered in the framework of RPA with effective residual forces.Comment: 10 pages and 2 figures,to appear in Yad. Fi

Spin Damping in an RF Atomic Magnetometer

Under negative feedback, the quality factor Q of a radio-frequency magnetometer can be decreased by more than two orders of magnitude, so that any initial perturbation of the polarized spin system can be rapidly damped, preparing the magnetometer for detection of the desired signal. We find that noise is also suppressed under such spin-damping, with a characteristic spectral response corresponding to the type of noise; therefore magnetic, photon-shot, and spin-projection noise can be measured distinctly. While the suppression of resonant photon-shot noise implies the closed-loop production of polarization-squeezed light, the suppression of resonant spin-projection noise does not imply spin-squeezing, rather simply the broadening of the noise spectrum with Q. Furthermore, the application of spin-damping during phase-sensitive detection suppresses both signal and noise in such a way as to increase the sensitivity bandwidth. We demonstrate a three-fold increase in the magnetometer's bandwidth while maintaining 0.3 fT/\surdHz sensitivity.Comment: 24 pages, 7 figure

Gravitational Couplings of Intrinsic Spin

The gravitational couplings of intrinsic spin are briefly reviewed. A consequence of the Dirac equation in the exterior gravitational field of a rotating mass is considered in detail, namely, the difference in the energy of a spin-1/2 particle polarized vertically up and down near the surface of a rotating body is $\hbar\Omega\sin\theta$. Here $\theta$ is the latitude and $\Omega = 2GJ/(c^2 R^3)$, where $J$ and $R$ are, respectively, the angular momentum and radius of the body. It seems that this relativistic quantum gravitational effect could be measurable in the foreseeable future.Comment: LaTeX file, no figures, 16 page

Nucleon Edm from Atomic Systems and Constraints on Supersymmetry Parameters

The nucleon EDM is shown to be directly related to the EDM of atomic systems. From the observed EDM values of the atomic Hg system, the neutron EDM can be extracted, which gives a very stringent constraint on the supersymmetry parameters. It is also shown that the measurement of Nitrogen and Thallium atomic systems should provide important information on the flavor dependence of the quark EDM. We perform numerical analyses on the EDM of neutron, proton and electron in the minimal supersymmetric standard model with CP-violating phases. We demonstrate that the new limit on the neutron EDM extracted from atomic systems excludes a wide parameter region of supersymmetry breaking masses above 1 TeV, while the old limit excludes only a small mass region below 1 TeV.Comment: 10 pages, 7 figure file

Quantum Theory in Accelerated Frames of Reference

The observational basis of quantum theory in accelerated systems is studied. The extension of Lorentz invariance to accelerated systems via the hypothesis of locality is discussed and the limitations of this hypothesis are pointed out. The nonlocal theory of accelerated observers is briefly described. Moreover, the main observational aspects of Dirac's equation in noninertial frames of reference are presented. The Galilean invariance of nonrelativistic quantum mechanics and the mass superselection rule are examined in the light of the invariance of physical laws under inhomogeneous Lorentz transformations.Comment: 25 pages, no figures, contribution to Springer Lecture Notes in Physics (Proc. SR 2005, Potsdam, Germany, February 13 - 18, 2005

Constraining supersymmetric models from B_d - B-bar_d mixing and the B_d --> J/psi K_S asymmetry

We analyze the chargino contributions to B_d - B-bar_d mixing and CP asymmetry of the B_d --> J/psi K_S decay, in the framework of the mass insertion approximation. We derive model independent bounds on the relevant mass insertions. Moreover, we study these contributions in supersymmetric models with minimal flavor violation, Hermitian flavor structure, and small CP violating phases and universal strength Yukawa couplings. We show that in supersymmetric models with large flavor mixing, the observed values of sin(2 beta) may be entirely due to the chargino-up-squark loops.Comment: 22 pages, 1 figure, minor corrections, version to appear in Phys. Rev.

Quantum computation with trapped polar molecules

We propose a novel physical realization of a quantum computer. The qubits are electric dipole moments of ultracold diatomic molecules, oriented along or against an external electric field. Individual molecules are held in a 1-D trap array, with an electric field gradient allowing spectroscopic addressing of each site. Bits are coupled via the electric dipole-dipole interaction. Using technologies similar to those already demonstrated, this design can plausibly lead to a quantum computer with $\gtrsim 10^4$ qubits, which can perform $\sim 10^5$ CNOT gates in the anticipated decoherence time of $\sim 5$ s.Comment: 4 pages, RevTeX 4, 2 figures. Edited for length and converted to RevTeX, but no substantial changes from earlier pdf versio

Muon Physics: A Pillar of the Standard Model

Since its discovery in the 1930s, the muon has played an important role in our quest to understand the sub-atomic theory of matter. The muon was the first second-generation standard-model particle to be discovered, and its decay has provided information on the (Vector -Axial Vector) structure of the weak interaction, the strength of the weak interaction, G_F, and the conservation of lepton number (flavor) in muon decay. The muon's anomalous magnetic moment has played an important role in restricting theories of physics beyond the standard standard model, where at present there is a 3.4 standard-deviation difference between the experiment and standard-model theory. Its capture on the atomic nucleus has provided valuable information on the modification of the weak current by the strong interaction which is complementary to that obtained from nuclear beta decay.Comment: 8 pages, 9 figures. Invited paper for the Journal of Physical Society in Japan (JPSJ), Special Topics Issue "Frontiers of Elementary Particle Physics, The Standard Model and beyond