A5048063893- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Advanced Frequency and Time Standards
- Quantum optics and atomic interactions
- Atomic and Molecular Physics
- Spectroscopy and Laser Applications
- Quantum Information and Cryptography
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Mechanical and Optical Resonators
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Quantum Electrodynamics and Casimir Effect
- Quantum chaos and dynamical systems
- Dark Matter and Cosmic Phenomena
- Inorganic Fluorides and Related Compounds
- Spectroscopy and Quantum Chemical Studies
- Molecular Spectroscopy and Structure
- Quantum Mechanics and Applications
- Experimental and Theoretical Physics Studies
- Photonic and Optical Devices
- Radioactive Decay and Measurement Techniques
- Semiconductor Lasers and Optical Devices
- Molecular spectroscopy and chirality
Imperial College London
2015-2024
Stony Brook University
1988-2014
University of Groningen
2014
Center for Free-Electron Laser Science
2014
Universität Hamburg
2014
Arizona State University
2014
University of Basel
2014
Yale University
1995-2005
Imperial Valley College
2004
University of Sussex
1996-2002
The most sensitive measurements of the electron electric dipole moment ${d}_{e}$ have previously been made using heavy atoms. Heavy polar molecules offer a greater sensitivity to because interaction energy be measured is typically ${10}^{3}$ times larger than in atom. We used YbF make first measurement this kind. Together, large and strong tensor polarizability molecule our experiment essentially free systematic errors that currently limit Our result...
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...
We demonstrate slowing and longitudinal cooling of a supersonic beam CaF molecules using counter-propagating laser light resonant with closed rotational almost vibrational transition. A group are decelerated by about 20 m/s applying fixed frequency for 1.8 ms. Their velocity spread is reduced, corresponding to final temperature 300 mK. The further reduced chirping the keep it in resonance as slow down.
We demonstrate one-dimensional sub-Doppler laser cooling of a beam YbF molecules to 100 μK. This is key step towards measurement the electron's electric dipole moment using ultracold molecules. compare effectiveness magnetically assisted and polarization-gradient mechanisms. model experiment find good agreement with our data.
We report the first measurements of microwave excitation and ionization excited hydrogen atoms for scaled frequencies ${n}_{0}^{3}\ensuremath{\omega}$ up to 2.8. Classical 3D calculations which directly model this 36.021-GHz experiment agree quite well ${n}_{0}^{3}\ensuremath{\omega}<1$, less $1\ensuremath{\le}{n}_{0}^{3}\ensuremath{\omega}\ensuremath{\le}2$, do not ${n}_{0}^{3}\ensuremath{\omega}>2$. This supports theoretical predictions that as rises above 1, quantal threshold fields rise...
We have decelerated a supersonic beam of $^{174}\mathrm{YbF}$ molecules using switched sequence electrostatic field gradients. These are 7 times heavier than any previously decelerated. An alternating gradient structure allows us to decelerate and focus the in their ground state. show that decelerator exhibits axial transverse stability required bring rest. Our work significantly extends range amenable this powerful method cooling trapping.
We explore the uses of ultracold molecules as a platform for future experiments in field quantum simulation, focusing on two molecular species, $^{40}$Ca$^{19}$F and $^{87}$Rb$^{133}$Cs. report development coherent state control using microwave fields both species; this is crucial ingredient many simulation applications. demonstrate proof-of-principle Ramsey interferometry measurements with fringe spacings $\sim 1~\rm kHz$ investigate dephasing time superposition $N=0$ $N=1$ rotational...
We recently reported a new measurement of the electron's electric dipole moment using YbF molecules (Hudson et al 2011 Nature 473 493). Here, we give more detailed description methods used to make this measurement, along with fuller analysis data. show how our isolate from imperfections in experiment that might mimic it. describe systematic errors discovered, and small corrections made account for these. By making set additional measurements greatly exaggerated experimental imperfections,...
We demonstrate coherent microwave control of the rotational, hyperfine, and Zeeman states ultracold CaF molecules, magnetic trapping these molecules in a single, selectable quantum state. trap about $5\ifmmode\times\else\texttimes\fi{}{10}^{3}$ for almost 2 s at temperature $70(8)\text{ }\text{ }\ensuremath{\mu}\mathrm{K}$ density $1.2\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$. measure state-specific loss rate due to collisions with background helium.
We propose an experiment to measure the electric dipole moment (EDM) of electron using ultracold YbF molecules. The molecules are produced as a thermal beam by cryogenic buffer gas source, and brought rest in optical molasses that cools them Doppler limit or below. molecular cloud is then thrown upward form fountain which EDM measured. A non-zero result would be unambiguous proof new elementary particle interactions, beyond standard model.
We introduce a scheme for deep laser cooling of molecules based on robust dark states at zero velocity. By simulating this scheme, we show it to be widely applicable method that can reach the recoil limit or below. demonstrate and characterize experimentally, reaching temperature 5.4(7) μK. solve general problem measuring low temperatures large clouds by rotating phase-space distribution then directly imaging complete velocity distribution. Using same rotation method, rapidly compress cloud....
A cloud of laser-cooled 85Rb atoms is coupled through a magnetic funnel into miniature waveguide formed by four current-carrying wires embedded in silica fiber. The atom has approximately 100 &mgr;m radius within the fiber and propagates over cm distances. We study coupling, propagation, transverse distribution fiber, find good agreement with theory. This prototype demonstrates feasibility guides as tool new field integrated optics, leading to single-mode propagation de Broglie waves...
We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap study their inelastic collisions. When the are prepared spin-stretched state component first rotationally excited state, they collide inelastically with rate coefficient k2=(6.6±1.5)×10−11 cm3/s at temperatures near 100 μK. attribute this to rotation-changing ground rotational we see no loss set an upper bound on spin-relaxation k2<5.8×10−12 95% confidence. compare these measurements results single-channel model...
Abstract The detection of variations fundamental constants the Standard Model would provide us with compelling evidence new physics, and could lift veil on nature dark matter energy. In this work, we discuss how a network atomic molecular clocks can be used to look for such unprecedented sensitivity over wide range time scales. This is precisely goal recently launched QSNET project: A measuring stability constants. will include state-of-the-art clocks, but also develop next-generation highly...
Experiments with cold molecules usually begin a molecular source. We describe the construction and characteristics of cryogenic buffer gas source CaF molecules. The emits pulses typical duration 240 μs, mean speed about 150 m/s, flux 5×1010 per steradian pulse in single rotational state.
Measurements of the electron's electric dipole moment (eEDM) are demanding tests physics beyond Standard Model. We describe how ultracold YbF molecules could be used to improve precision eEDM measurements by two three orders magnitude. Using numerical simulations, we show combination magnetic focussing, two-dimensional transverse laser cooling, and frequency-chirped slowing, can produce an intense, slow, highly-collimated molecular beam. make a magneto-optical trap loaded into optical...
We present an atom interferometer using large momentum transfer without $k$-reversal. More specifically, we use a microwave $\pi$/2 pulse to manipulate the spin state of $^{87}$Rb atoms before applying Raman light $\pi$ achieve 4$\hbar k$ per pulse. A in middle sequence reverses states, which allows closing arms by same pulses discuss scalability this technique. Our results extend scope optics into interferometers where $k$-reversal are not available.
Abstract Using a mid-infrared quantum cascade laser and wavelength modulation absorption spectroscopy, we measure the frequencies of ro-vibrational transitions N 2 O in 17 μm region with uncertainties below 5 MHz. These lines, corresponding to bending mode molecule, can be used for calibration spectrometers this spectral region. We present model lineshapes features spectroscopy that takes into account Doppler broadening, collisional saturation absorption, lineshape distortion due frequency...
We present the design and characterization of a low-noise environment for measuring electron's electric dipole moment (EDM) with beam molecules. To minimize magnetic Johnson noise from metals, features ceramic field plates housed in glass vacuum chamber. suppress external apparatus is enclosed within cylindrical four-layer mu-metal shield shielding factor exceeding $10^6$ one radial direction $10^5$ other. Finite element modelling shows that difference between these factors due to imperfect...
We report the first laser-radio-frequency double resonance spectrum of a simple lanthanide compound, paramagnetic radical 174YbF. Measurements rf intervals as function rotational quantum number N allow us to determine precise spin-rotation and fluorine hyperfine interaction coupling constants for X 2Σ+(v=0 v=1) ground states The results v=0 are γ0=−13.424 00(16) MHz, γ1=3.982 3(11) kHz, γ2=−25(1) mHz, b0=141.795 6(5) b1=−0.510(11) c=85.402 6(14) C=20.38(13) kHz. For v=1 they γ0=−33.811 8(7)...
We have produced a Bose-Einstein condensate on permanent-magnet atom chip based periodically magnetized videotape. observe the expansion and dynamics of in one microscopic waveguides close to surface. The lifetime for atoms remain trapped near this dielectric material is significantly longer than above metal surface same thickness. These results illustrate suitability structures quantum-coherent preparation manipulation cold atoms.
Using frequency-chirped radiation pressure slowing, we precisely control the velocity of a pulsed CaF molecular beam down to few m s–1, compressing its spread by factor 10 while retaining high intensity: at 15 s–1 flux, measured 1.3 from source, is 7 × 105 molecules per cm2 shot in single rovibrational state. The suitable for loading magneto-optical trap or, when combined with transverse laser cooling, improving precision spectroscopic measurements that test fundamental physics. We compare...
Abstract The electric dipole moment of the electron (eEDM) can be measured with high precision using heavy polar molecules. In this paper, we report on a series new techniques that have improved statistical sensitivity YbF eEDM experiment. We increase number molecules participating in experiment by an order magnitude carefully designed optical pumping scheme. also detection efficiency these another cycling addition, show how to destabilise dark states and reduce backgrounds otherwise limit...