arXiv subjects

D. Budker

Publications and source records attributed to D. Budker.

At least 91 records · Page 5Linked to original sources

arXiv2012

Pressure broadening and shift of D1 line of Ag by He, Ar and N2

We have studied experimentally pressure broadening and shift of Ag D1 line caused by He, Ar and N2 buffer gases. The measurements were done in a heat-pipe type absorption cell at a temperature of ~1000 K and gas pressures up to 1000 torr. The measured values for pressure broadening and shift (in MHz/Torr) are as follows: Ag-He 5.8(1), +1.16(2); Ag-Ar 5.2(2), -2.28(4); Ag-N2 5.2(1), -2.52(7). The "+" and "-" signs indicate the direction for the shifts to the blue and red side of the spectrum, respectively.

physics.atom-ph↗

arXiv2011

From yeV to TeV: Search for the Neutron Electric Dipole Moment

The existence of electric dipole moments (EDM) for fundamental particles signals time-reversal symmetry (T) violation accompanied by violation of parity (P); only upper limits have been established to date. Time-reversal violation in turn implies CP violation under the assumption that CPT is a good symmetry. The neutron is an attractive system for an EDM search, both because it is neu- tral and because a neutron EDM would be relatively easier to interpret than the comparable quantity for a nucleus or even an atom. We introduce briefly the key experimental requirements for such search and describe some aspects of the neutron EDM experiment planned for the Spallation Neutron Source at the U.S. Oak Ridge National Laboratory.

nucl-ex↗

arXiv2011

Atomic parity violation in two-photon J=0-to-1 transitions

We present a method for measuring nuclear-spin-dependent atomic parity violation without nuclear-spin-independent background. Such measurements can be achieved by observing interference of parity-conserving and parity-violating two-photon J=0-to-1 transitions driven by collinear photons of the same frequency in the presence of an external static magnetic field.

physics.atom-ph↗

arXiv2011

Parity violation in two-photon J=0-to-1 transitions: Analysis of systematic errors

We present an analysis of systematic sources of uncertainty in a recently proposed scheme for measurement of nuclear-spin-dependent atomic parity violation using two-photon J=0-to-1 transitions driven by collinear photons of the same frequency in the presence of a static magnetic field. Two important sources of uncertainty are considered: misalignment of applied fields, and stray electric and magnetic fields. The parity-violating signal can be discriminated from systematic effects using a combination of field reversals and analysis of the Zeeman structure of the transition.

physics.atom-ph↗

arXiv2011

All-optical atomic magnetometers based on nonlinear magneto-optical rotation with amplitude modulated light

We demonstrate a magnetometric technique based on nonlinear magneto-optical rotation using amplitude modulated light. The magnetometers can be operated in either open-loop (typical nonlinear magneto-optical rotation with amplitude-modulated light) or closed-loop (self-oscillating) modes. The latter mode is particularly well suited for conditions where the magnetic field is changing by large amounts over a relatively short timescale.

physics.atom-ph↗

arXiv2011

Atomic parity violation in 0-to-0 two-photon transitions

We present a method for measuring atomic parity violation in the absence of static external electric and magnetic fields. Such measurements can be achieved by observing the interference of parity conserving and parity violating two-photon transition amplitudes between energy eigenstates of zero electronic angular momentum. General expressions for induced two-photon transition amplitudes are derived. The signal-to-noise ratio of a two-photon scheme using the 6s^2 1S0 to 6s6p 3P0 transition in ytterbium is estimated.

physics.atom-ph↗

arXiv2010

Optical properties of the nitrogen-vacancy singlet levels in diamond

We report measurements of the optical properties of the 1042 nm transition of negatively-charged Nitrogen-Vacancy (NV) centers in type 1b diamond. The results indicate that the upper level of this transition couples to the m_s=+/-1 sublevels of the {^3}E excited state and is short-lived, with a lifetime <~ 1 ns. The lower level is shown to have a temperature-dependent lifetime of 462(10) ns at 4.4 K and 219(3) ns at 295 K. The light-polarization dependence of 1042 nm absorption confirms that the transition is between orbitals of A_1 and E character. The results shed new light on the NV level structure and optical pumping mechanism.

quant-ph↗

arXiv2010

Broadband magnetometry by infrared-absorption detection of nitrogen-vacancy ensembles in diamond

We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast, and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume $50 \times 50 \times 300$ microns^3, we project photon shot-noise limited sensitivity of 5 pT in one second of acquisition and bandwidth from dc to a few megahertz. Operation in a gradiometer configuration yields a noise floor of 7 nTrms at ~110 Hz in one second of acquisition.

physics.ins-det↗

arXiv2010

Investigation of Anti-Relaxation Coatings for Alkali-Metal Vapor Cells Using Surface Science Techniques

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of anti-relaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10,000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings, in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge X-ray absorption fine structure spectroscopy, and X-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin anti-relaxation coatings, as well as the design and synthesis of new classes of coating materials.

physics.chem-ph↗

arXiv2010

Constraints on anomalous spin-spin interactions from spin-exchange collisions

Measured and calculated cross sections for spin-exchange between alkali atoms and noble gases (specifically sodium and helium) are used to constrain anomalous spin-dependent forces between nuclei at the atomic scale ($\sim 10^{-8}~{\rm cm}$). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for a heretofore undiscovered axial vector interaction of the neutron arising from exchange of a boson of mass $\lesssim 100~{\rm eV}$ is constrained to be $g_A^n/\sqrt{4 π\hbar c} < 2 \times 10^{-3}$. Constraints are established for a velocity- and spin-dependent interaction $\propto \prn{\mathbf{I} \cdot \mathbf{v}} \prn{\mathbf{K} \cdot \mathbf{v}}$, where $\mathbf{I}$ and $\mathbf{K}$ are the nuclear spins of He and Na, respectively, and $\mathbf{v}$ is the relative velocity of the atoms. Constraints on torsion gravity are also considered.

physics.atom-ph↗

arXiv2010

Measurement of dynamic Stark polarizabilities by analyzing spectral lineshapes of forbidden transitions

We present a measurement of the dynamic scalar and tensor polarizabilities of the excited state 3D1 in atomic ytterbium. The polarizabilities were measured by analyzing the spectral lineshape of the 408-nm 1S0->3D1 transition driven by a standing wave of resonant light in the presence of static electric and magnetic fields. Due to the interaction of atoms with the standing wave, the lineshape has a characteristic polarizability-dependent distortion. A theoretical model was used to simulate the lineshape and determine a combination of the polarizabilities of the ground and excited states by fitting the model to experimental data. This combination was measured with a 13% uncertainty, only 3% of which is due to uncertainty in the simulation and fitting procedure. The scalar and tensor polarizabilities of the state 3D1 were measured for the first time by comparing two different combinations of polarizabilities. We show that this technique can be applied to similar atomic systems.

physics.atom-ph↗

arXiv2010

Nonlinear magneto-optical rotation in the presence of radio-frequency field

We report measurements of nonlinear magneto-optical rotation (NMOR) for the D2 line of $^{87}$Rb atoms in an antirelaxation-coated vapor cell in the presence of a radio-frequency (rf) field. The experimental NMOR signals as a function of rf field frequency for various rf field powers are compared to a theoretical model based on the density-matrix formalism. The comparison between experiment and theory enables understanding of the ground-state atomic spin polarization dynamics, illustrated using plots of the probability distribution of the atomic angular momentum.

physics.atom-ph↗

arXiv2010

Precision polarimetry with real-time mitigation of optical-window birefringence

Optical-window birefringence is frequently a major obstacle in experiments measuring changes in the polarization state of light traversing a sample under investigation. It can contribute a signal indistinguishable from that due to the sample and complicate the analysis. Here, we explore a method to measure and compensate for the birefringence of an optical window using the reflection from the last optical surface before the sample. We demonstrate that this arrangement can cancel out false signals due to the optical-window birefringence-induced ellipticity drift to about 1%, for the values of total ellipticity less than 0.25 rad.

physics.optics↗

arXiv2010

Rubidium dimers in paraffin-coated cells

Measurements were made to determine the density of rubidium dimer vapor in paraffin-coated cells. The number density of dimers and atoms in similar paraffin-coated and uncoated cells was measured by optical spectroscopy. Due to the relatively low melting point of paraffin, a limited temperature range of 43-80 deg C was explored, with the lower end corresponding to a dimer density of less than 10^7 cm^(-3). With one-minute integration time, a sensitivity to dimer number density of better than 10^6 cm^(-3) was achieved. No significant difference in dimer density was observed between the cells.

physics.atom-ph↗

arXiv2010

Transverse laser cooling of a thermal atomic beam of dysprosium

A thermal atomic beam of dysprosium (Dy) atoms is cooled using the $4f^{10}6s^2 (J=8) \to 4f^{10}6s6p (J=9)$ transition at 421 nm. The cooling is done via a standing light wave orthogonal to the atomic beam. Efficient transverse cooling to the Doppler limit is demonstrated for all observable isotopes of dysprosium. Branching ratios to metastable states are demonstrated to be $<5\times10^{-4}$. A scheme for enhancement of the nonzero-nuclear-spin-isotope cooling, as well as a method for direct identification of possible trap states, is proposed.

physics.atom-ph↗

arXiv2010

Temperature dependence of the nitrogen-vacancy magnetic resonance in diamond

The temperature dependence of the magnetic resonance spectra of nitrogen-vacancy (NV-) ensembles in the range of 280-330 K was studied. Four samples prepared under different conditions were studied with NV- concentrations ranging from 10 ppb to 15 ppm. For all of these samples, the axial zero-field splitting (ZFS) parameter, D, was found to vary significantly with temperature, T, as dD/dT = -74.2(7) kHz/K. The transverse ZFS parameter, E, was non-zero (between 4 and 11 MHz) in all samples, and exhibited a temperature dependence of dE/(EdT) = -1.4(3) x 10^(-4) K^(-1). The results might be accounted for by considering local thermal expansion. The observation of the temperature dependence of the ZFS parameters presents a significant challenge for room-temperature diamond magnetometers and may ultimately limit their bandwidth and sensitivity.

cond-mat.mes-hall↗

arXiv2010

Spectroscopic test of Bose-Einstein statistics for photons

Using Bose-Einstein-statistics-forbidden two-photon excitation in atomic barium, we have limited the rate of statistics-violating transitions, as a fraction $ν$ of an equivalent statistics-allowed transition rate, to $ν<4.0\times10^{-11}$ at the 90% confidence level. This is an improvement of more than three orders of magnitude over the best previous result. Additionally, hyperfine-interaction enabling of the forbidden transition has been observed, to our knowledge, for the first time.

physics.atom-ph↗

arXiv2010

Parity violation in atomic ytterbium: experimental sensitivity and systematics

We present a detailed description of the observation of parity violation in the 1S0-3D1 408-nm forbidden transition of ytterbium, a brief report of which appeared earlier. Linearly polarized 408-nm light interacts with Yb atoms in crossed E- and B-fields. The probability of the 408-nm transition contains a parity violating term, proportional to (Elight . B)[(E x Elight) . B], arising from interference between the parity violating amplitude and the Stark amplitude due to the E-field (Elight is the electric field of the light). The transition probability is detected by measuring the population of the 3P0 state, to which 65% of the atoms excited to the 3D1 state spontaneously decay. The population of the 3P0 state is determined by resonantly exciting the atoms with 649-nm light to the 6s7s 3S1 state and collecting the fluorescence resulting from its decay. Systematic corrections due to E-field and B-field imperfections are determined in auxiliary experiments. The statistical uncertainty is dominated by parasitic frequency excursions of the 408-nm excitation light due to imperfect stabilization of the optical reference with respect to the atomic resonance. The present uncertainties are 9% statistical and 8% systematic. Methods of improving the accuracy for the future experiments are discussed.

physics.atom-ph↗