A5026708891- Cold Atom Physics and Bose-Einstein Condensates
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Atomic and Molecular Physics
- Atomic and Subatomic Physics Research
- Laser Design and Applications
- Quantum, superfluid, helium dynamics
- Quantum optics and atomic interactions
- Photorefractive and Nonlinear Optics
- Quantum Mechanics and Applications
- Laser-induced spectroscopy and plasma
- Quantum many-body systems
- Solid State Laser Technologies
- Quantum Information and Cryptography
- Mass Spectrometry Techniques and Applications
- Molecular spectroscopy and chirality
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- Electrochemical Analysis and Applications
- Nuclear physics research studies
- Scientific Measurement and Uncertainty Evaluation
- Cold Fusion and Nuclear Reactions
- Dark Matter and Cosmic Phenomena
- Laser-Matter Interactions and Applications
- Water Quality Monitoring and Analysis
University of Oxford
1992-2024
Science Oxford
2024
Clarendon College
1984-1995
Oxford Lasers (United Kingdom)
1991-1994
Stanford University
1985-1989
U.S. National Science Foundation
1986
We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory Network), a proposed programme using cold strontium atoms to search for ultra-light dark matter, explore gravitational waves in mid-frequency range between peak sensitivities LISA LIGO/Virgo/ KAGRA/INDIGO/Einstein Telescope/Cosmic Explorer experiments, probe other frontiers fundamental physics. would complement planned searches as well mergers involving intermediate-mass black holes...
Abstract We propose in this White Paper a concept for space experiment using cold atoms to search ultra-light dark matter, and detect gravitational waves the frequency range between most sensitive ranges of LISA terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment Dark Matter Gravity Exploration (AEDGE), will also complement other planned searches exploit synergies with wave detectors. give examples extended sensitivity matter offered...
We present an investigation of the cesium magneto-optical trap, with particular regard to best combination atomic density and temperature that can be produced. Conditions in trap depend on four independent parameters: detuning intensity light, gradient magnetic field, number atoms trapped. have varied all these parameters measured distribution trapped cloud. Both nonlinear variation position restoring force reabsorption photons scattered cloud limit maximum density, we empirical model takes...
Abstract Quantum vortices play a crucial role in both equilibrium and dynamical phenomena two-dimensional (2D) superfluid systems. Experimental detection of these excitations 2D ultracold atomic gases typically involves examining density depletions absorption images, however the presence significant phononic background renders problem challenging, beyond capability simple algorithms or human eye. Here, we utilize convolutional neural network (CNN) to detect strong long- intermediate-length...
We have determined the 1S Lamb shift in atomic hydrogen with a precision of 2 parts ${10}^{4}$ by measuring frequency 1S-2S transition observed continuous-wave Doppler-free two-photon spectroscopy. employ an interferometrically calibrated absorption line $^{130}\mathrm{Te}_{2}$ as our reference and obtain interval 466 061 413.8(1.5) MHz. Choosing value Rydberg constant measured independently high-resolution spectroscopy Balmer-\ensuremath{\beta} transition, we find to be 8173.3(1.7) MHz,...
We have observed the narrow 1S-2S transition in hydrogen and deuterium with high resolution using Doppler-free two-photon absorption of continuous-wave 243-nm light. The frequencies were measured by direct comparison accurately calibrated lines spectrum $^{130}\mathrm{Te}_{2}$ molecule. find interval to be 2 466 061 414.1(8) MHz 732 408.5(7) deuterium. By combining these results recent measurements Rydberg constant we obtain values 8172.6(7) 8183.7(6) for 1S Lamb shifts deuterium,...
Improved measurements of isotope shifts in the 4s2 1S0-4s5s 1S0 transition calcium are reported for stable isotopes. A comparison with shift other transitions by means a King plot shows satisfactory agreement. Values changes mean-square nuclear charge radius delta (r2) from combined analysis muonic and electron scattering data used to separate mass field optical lines. This procedure leads values isotopes 40Ca 48Ca using all available high-precision data. The results (r2)A,40 3.2(2.5), 215.3...
We have observed the $1S\ensuremath{-}2S$ transition in atomic hydrogen gas with a resolution of 5 parts ${10}^{9}$ by Doppler-free two-photon spectroscopy, using multimilliwatt cw radiation near 243 nm generated sum-frequency mixing. The experiment opens way to substantial increases accuracy Rydberg constant, electron/proton mass ratio, and Lamb shift $1S$ ground state.
We probe local phase fluctuations of trapped two-dimensional Bose gases using matter-wave interferometry. This enables us to measure the correlation function, which changes from an algebraic exponential decay when system crosses Berezinskii-Kosterlitz-Thouless (BKT) transition. determine temperature dependence BKT exponent η and find critical value η_{c}=0.17(3) for our system. Furthermore, we vortex density as a function phase-space density, shows scale-invariant behavior across Our...
We have measured the 1S-2S transition frequency in atomic hydrogen with a precision of 7 parts ${10}^{10}$ by continuous-wave Doppler-free two-photon spectroscopy. employ cavity-enhanced multimilliwatt radiation near 243 nm produced sum-frequency generation, and we observe low-pressure hydrogen-helium cell resolution 3 ${10}^{9}$. For comparison detect an optical heterodyne signal at difference between 243-nm light used to excite second harmonic reference laser locked interferometrically...
Abstract The development of laser cooling has an important impact on many aspects atomic physics and quantum optics. efforts to understand the various types force exerted atoms by light have led some interesting it is now possible for extremely cold clouds be produced, which can confined in atom traps or formed into very monoenergetic beams. There are new possibilities explore this ultra-cold regime where effects significant, addition potential great improvements precision measurements made...
Isotope shifts and pressure broadening have been measured in the two-photon transition at 249 nm from 5p6 1S0 ground level of neutral xenon to a J=0 5p56p configuration (the 2p5 Paschen notation). A continuous-wave tunable dye laser operating 498 with intracavity frequency doubling excited transition. The work is first application Doppler-free spectroscopy involving rare gas. results show that although no s electron directly involved transition, field isotope are comparable those observed...
We investigate cold bosonic impurity atoms trapped in a vortex lattice formed by condensed bosons of another species. describe the dynamics impurities Hubbard model containing occupation-dependent parameters to capture effects strong impurity-impurity interactions. These include both repulsive direct interaction and an attractive effective mediated BEC. The occupation dependence these two competing interactions drastically affects phase diagram, including causing disappearance some Mott lobes
Magneto-optical traps (MOTs) are widely used for laser cooling of atoms. We have developed a high-flux compact cold-atom source based on pyramid MOT with unique adjustable aperture that is highly suitable portable quantum technology devices, including space-based experiments. The adjustability enabled an investigation into the previously unexplored impact size atomic flux, and optimisation allowed us to demonstrate higher flux than any reported sources use pyramid, LVIS, 3D-MOT or grating...
While renormalization group theory is a fully established method to capture equilibrium phase transitions, the applicability of RG universal non-equilibrium behavior remains elusive. Here we address this question by measuring dynamics triggered quench from superfluid thermal across Berezinskii-Kosterlitz-Thouless transition in 2D Bose gas. We system splitting gas two and probe relaxation correlation function vortex density via matter-wave interferometry. The occur two-step process rapid...
Investigating out-of-equilibrium dynamics with two-dimensional (2D) systems is of widespread theoretical interest, as these are strongly influenced by fluctuations and there exists a superfluid phase transition at finite temperature. In this work, we realise matter-wave interference for degenerate Bose gases, including the first demonstration coherent splitting 2D gases using magnetic trapping potentials. We improve fringe contrast imaging only thin slice expanded atom clouds, which will be...
We have calculated the long-range part of momentum diffusion coefficient two atoms in a radiation field using an S-matrix expansion to first order dipole-dipole interaction between atoms. This perturbative treatment is limited low-saturation regime and large detunings (\ensuremath{\Vert}\ensuremath{\delta}\ensuremath{\Vert}\ensuremath{\gg}\ensuremath{\gamma}). The physical processes arise from with coherent incoherent parts scattering spectrum. find that constant density extra term when...
In this paper, we give a theoretical description of resonant coupling between two collective excitations Bose-condensed gas on, or close to, second-harmonic resonance. Using analytic expressions for the quasiparticle wave functions, show that quadrupole modes is strong, leading to time few milliseconds (for TOP trap with radial frequency $\ensuremath{\sim}100 \mathrm{Hz}$ and $\ensuremath{\sim}{10}^{4}$ atoms). hydrodynamic approximation, derive an expression matrix element. These can be...
We examine how nondestructive measurements generate spin squeezing in an atomic Bose-Einstein condensate confined a double-well trap. The each well is monitored using coherent light beams Mach-Zehnder configuration that interacts with the atoms through quantum nondemolition Hamiltonian. solve dynamics of light-atom system exact wave-function approach, presence dephasing noise, which allows us to arbitrary interaction times and general initial state. find monitoring at zero detection current...
The understanding of nonequilibrium dynamics in many-body quantum systems is a fundamental issue statistical physics. Experiments that probe universal properties these can address such foundational questions. In this study, we report the measurement triggered by quench from superfluid to normal phase across Berezinskii-Kosterlitz-Thouless transition two-dimensional (2D) Bose gas. We reduced density splitting 2D gas two, realizing critical point. subsequent relaxation were probed with...
Recently reported measurements of optical isotope shifts in zinc for isotopes with mass numbers 64, 66, 67, 68 and 70 are interpreted terms variations the nuclear charge distribution. The shifts, which were measured transition 3d 10 4p 2 P ½ -3d 9 4s D 3/2 Zn II at 589.4 nm, separated into field contributions. relative as follows: 64; 1.0, 68, 66; 0.84 +0.04 -0.06 , 70, 68; 0.97 +0.06 -0.04 . 0.19 +0.09 -0.13 These proportional to corresponding differences δ< r > mean square radii....
Isotope shifts of all the stable isotopes and hyperfine splittings 115Sn, 117Sn 119Sn have been measured in transitions 5s25p23P0-5s25p6s3P1 at 286 nm Sn I. Tin atoms a collimated beam to reduce Doppler width were excited by radiation generated frequency doubling light from CW ring dye laser. Spectra recorded monitoring subsequent decay calibrated optical heterodyning. The relative positions are, MHz: 112; 0.0(1.0), 114;319.5(1.3), 115;412.7(1.1), 116;640.0(0.6), 117;746.8(0.7),...