A5001047738- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Frequency and Time Standards
- Atomic and Molecular Physics
- Scientific Measurement and Uncertainty Evaluation
- Quantum, superfluid, helium dynamics
- Advanced Fiber Laser Technologies
- Quantum optics and atomic interactions
- Radioactive Decay and Measurement Techniques
- Spectroscopy and Quantum Chemical Studies
- Dark Matter and Cosmic Phenomena
- Quantum Mechanics and Applications
- Advanced Chemical Physics Studies
- Quantum Information and Cryptography
- Particle accelerators and beam dynamics
- Laser Design and Applications
- Photonic and Optical Devices
- Electron and X-Ray Spectroscopy Techniques
- Various Chemistry Research Topics
- Experimental and Theoretical Physics Studies
- Nuclear Physics and Applications
- Electrochemical Analysis and Applications
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Molecular spectroscopy and chirality
University of Toronto
2016-2024
York University
2012-2015
Yale University
2010-2011
Indian Institute of Technology Kanpur
2006
Chhatrapati Shahu Ji Maharaj University
2005
Stubbornly Spherical The shape of the electron's charge distribution reflects degree to which switching direction time impacts basic ingredients universe. Standard Model (SM) particle physics predicts a very slight asphericity distribution, whereas SM extensions such as supersymmetry posit bigger and potentially measurable, but still tiny, deviations from perfect sphere. Polar molecules have been identified ideal settings for measuring this asymmetry, should be reflected in finite electric...
Unraveling the proton puzzle The discrepancy between size deduced from Lamb shift in muonic hydrogen and average, textbook value based on regular (electronic) has puzzled physicists for nearly a decade. One possible resolution could be that electrons interact with protons different way than muons do, which would require “new physics.” Bezginov et al. measured electronic hydrogen, allowed direct comparison to hydrogen. two results agreed, but averaged remains. Science , this issue p. 1007
The electric dipole moment of the electron (eEDM) is a signature CP-violating physics beyond Standard Model. We describe an ongoing experiment to measure or set improved limits eEDM, using cold beam thorium monoxide (ThO) molecules. metastable $H {}^3\Delta_1$ state in ThO has important advantages for such experiment. argue that statistical uncertainty eEDM measurement could be by as much 3 orders magnitude compared current experimental limit, first-generation apparatus beam. our...
We recently set a new limit on the electric dipole moment of electron (eEDM) (J. Baron et al., ACME collaboration, Science 343 (2014), 269-272), which represented an order-of-magnitude improvement previous and placed more stringent constraints many CP-violating extensions to Standard Model. In this paper we discuss measurement in detail. The experimental method associated apparatus are described, together with techniques used isolate eEDM signal. particular, detail way switches were suppress...
We propose a very sensitive method for measuring the electric dipole moment of electron using polar molecules embedded in cryogenic solid matrix inert-gas atoms. The can be oriented $\hat{\rm{z}}$ direction by an applied field, as has recently been demonstrated Park, et al. [Angewandte Chemie {\bf 129}, 1066 (2017)]. trapped are prepared into state which its spin perpendicular to $\hat{\rm{z}}$, and magnetic field along causes precession this spin. An $d_e$ would affect due up 100~GV/cm...
Heavy polar diatomic molecules are the primary tools for searching T-violating permanent electric dipole moment of electron (eEDM). Valence electrons in some experience extremely large effective fields due to relativistic interactions. These crucial success polar-molecule-based eEDM search experiments. Here we report on results ab initio calculations a series that highly sensitive an eEDM, mercury monohalides (HgF, HgCl, HgBr, and HgI). We study influence halide anions E_{eff}, identify HgBr...
Because molecules can have their orientation locked when embedded into a solid rare-gas matrix, hyperfine structure is strongly perturbed relative to the freely rotating molecule. The addition of an electric field further perturbs structure, and fields parallel antiparallel molecular result in different shifts structure. These enable selective detection with orientations axes crystal, which will be important ingredient improved electron dipole moment measurement using large ensembles polar...
Open quantum systems interacting with a thermal environment are formally treated by secular or nonsecular master equations, the equation predicting distinct dynamics unobserved noise-induced Fano coherences. The authors propose an experimental test to examine master-equation applicability and existence of coherences in atomic system excited incoherent light.
Cryogenically cooled buffer gas beam sources of the molecule thorium monoxide (ThO) are optimized and characterized. Both helium neon shown to produce ThO beams with high flux, low divergence, forward velocity, cold internal temperature for a variety stagnation densities nozzle diameters. The operates density ∼10(15)-10(16) cm(-3) (Reynolds number ∼1-100), resulting in expansion cooling as 2 K. For (helium) based source, this represents by factor about 10 (2) from initial 20 K (4 K). These...
The metastable $H \ {}^3\Delta_1$ state in the thorium monoxide (ThO) molecule is highly sensitive to presence of a CP-violating permanent electric dipole moment electron (eEDM). magnetic $\mu_H$ and molecule-fixed $D_H$ this are measured preparation for search eEDM. small $\mu_H = 8.5(5) \times 10^{-3} \mu_B$ displays predicted cancellation spin orbital contributions ${}^3 \Delta_1$ paramagnetic molecular state, providing significant advantage suppression field noise related systematic...
Ultracold molecular gases are promising as an avenue to rich many-body physics, quantum chemistry, information, and precision measurements. This richness, which flows from the complex internal structure of molecules, makes creation ultracold using traditional methods (laser plus evaporative cooling) a challenge, in particular due spontaneous decay molecules into dark states. We propose way circumvent this key bottleneck all-optical method for decelerating stimulated absorption emission with...
Permanent electric dipole moments (EDMs) of fundamental particles such as the electron are signatures parity and time-reversal violation due to physics beyond standard model. EDM measurements probe new at energy scales well reach present-day colliders. Recent advances in assembling molecules from ultracold atoms have opened up opportunities for improving experiments. But better measurement techniques, that not limited by magnetic field sensitivity molecules, necessary before these can be...
We have trapped BaF molecules in neon ice, and used laser-induced fluorescence spectroscopy to map out optical transitions the molecules. Our measurements show that lattice does not significantly perturb certain one of these polarize electron spins, detect spin flips measure hyperfine molecules, entirely using lasers. This demonstration with heavy polar opens up new opportunities for precision beyond-standard-model physics.
Heavy diatomic molecules have been identified as good candidates for use in electron electric dipole moment (eEDM) searches. Suitable molecular species can be produced pulsed beams, but with a total flux and/or temporal evolution that varies significantly from pulse to pulse. These variations degrade the experimental sensitivity changes spin precession phase of an electri- cally polarized state, which is observable interest eEDM measurement. We present two methods measurement provide...
A frequency-offset separated-oscillatory-field technique is presented. The a modification of the Ramsey method separated oscillatory fields [Phys. Rev. 76, 996 (1949)], in which frequencies two are slightly offset from each other, so that relative phase varies continuously with time. With this technique, detection signal oscillates time at frequency, and resonance frequency obtained by using simple straight-line fit signal. has advantages being insensitive to response experimental system,...
We investigate the electromagnetic response of a periodic checker- board consisting alternating rectangular cells positive refractive index (ε = +1, μ +1) and negative −1, −1). show that system has peculiar imaging properties in it reproduces images source one cell every other cell. Using coordinate transformations, we map this into class systems three dimensions orthogonal planes delimiting eight cubical regions media sharing same vertex. also generalize these results to more general...
Gravitational waves (GWs) imprint apparent Doppler shifts on the frequency of photons propagating between an emitter and detector light. This forms basis a method to detect GWs using velocimetry pairs satellites. Operating in micro-hertz milli-hertz gravitational band, this could lead direct detection GWs. The crucial component such detectors is standard board emitting receiving Recent developments atomic standards have led devices that are approaching sensitivity required from...
Collisions with background gas can perturb the transition frequency of trapped ions in an optical atomic clock. We develop a nonperturbative framework based on quantum channel description scattering process and use it to derive master equation which leads simple analytic expression for collisional shift. As demonstration our method, we calculate shift ${\mathrm{Sr}}^{+}$ clock due elastic collisions helium.
We report on random lasing action in zinc oxide microparticles dispersed organic disordered hybrid polymer. Lasing from zinc-oxide–polymer is reported at temperature ranging 6to250K. Coherent backscattering measurements reveal that the transport of light sample diffusive and feedback for incoherent. The particles provide both gain scattering whereas polymer matrix offers ease material fabrication.
Precision measurements with atoms and molecules can search for subtle violations of time-reversal symmetry (T) in nuclei, thereby probe a variety new physics models. We present detailed scheme nuclear T-violation experiment using $^{153}$Eu$^{3+}$ ions doped non-centrosymmetric sites within Y$_2$SiO$_5$ crystal. The this solid contain nuclei that are highly sensitive to T-violation, avail large atomic enhancements by being polarized the solid. But particular, system methods we discuss here...
We find a simple solution to the problem of probe laser light shifts in two-photon optical atomic clocks. show that there exists magic polarization at which two states involved clock transition are identical. calculate differential polarizability as function for clocks based on neutral calcium and strontium, estimate angle these clocks, determine extent can be suppressed. shift excitation rate independently controlled using polarization.
Equation (11) in the published version of this article was missing a couple terms. The corrected equation can be found pdf file.
Measurement of a non-zero electric dipole moment (EDM) the electron within few orders magnitude current best limit |de| < 1.05 × 10−27 e⋅cm [1] would be an indication physics beyond Standard Model. The ACME Collaboration is searching for EDM by performing precision measurement spin precession in metastable H3Δ1 state thorium monoxide (ThO) using slow, cryogenic beam. We discuss status experiment. Based on data set acquired from 14 hours running time over period 2 days, we have achieved...
The Landau-Zener formula provides the probability of non-adiabatic transitions occuring when two energy levels are swept through an avoided crossing. is derived here in a simple calculation that emphasizes physics responsible for population transfer.