A5060629138- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Advanced Frequency and Time Standards
- Quantum optics and atomic interactions
- Quantum, superfluid, helium dynamics
- Advanced Fiber Laser Technologies
- Spectroscopy and Laser Applications
- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Dark Matter and Cosmic Phenomena
- Quantum Information and Cryptography
- Atomic and Molecular Physics
- Optical properties and cooling technologies in crystalline materials
- Advanced NMR Techniques and Applications
- Molecular spectroscopy and chirality
- Various Chemistry Research Topics
- Quantum Electrodynamics and Casimir Effect
- CCD and CMOS Imaging Sensors
- Scientific Measurement and Uncertainty Evaluation
- Superconducting Materials and Applications
- Quantum Mechanics and Applications
- Terahertz technology and applications
- Cardiovascular Syncope and Autonomic Disorders
- Quantum Chromodynamics and Particle Interactions
- Radiation Therapy and Dosimetry
Columbia University
2015-2024
University of Copenhagen
2022
Queen's University Belfast
2019
National Institute of Standards and Technology
2005-2008
University of Colorado Boulder
2005-2008
Joint Institute for Laboratory Astrophysics
2007-2008
University of Colorado System
2005-2007
Harvard University
2005
Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these require direct comparisons between them. We have realized a high-performance remote comparison optical over kilometer-scale urban distances, key step for development, dissemination, application standards. Through this proper design lattice-confined neutral atoms clock operation, we evaluate uncertainty strontium (Sr) lattice 1 × 10 –16...
The $^1\mathrm{S}_0$-$^3\mathrm{P}_0$ clock transition frequency $ν_\text{Sr}$ in neutral $^{87}$Sr has been measured relative to the Cs standard by three independent laboratories Boulder, Paris, and Tokyo over last years. agreement on $1\times 10^{-15}$ level makes best agreed-upon optical atomic frequency. We combine periodic variations with $^{199}$Hg$^+$ H-maser data test Local Position Invariance obtaining strongest limits date gravitational-coupling coefficients for fine-structure...
We propose a precision measurement of time variations the proton-electron mass ratio using ultracold molecules in an optical lattice. Vibrational energy intervals are sensitive to changes ratio. In contrast measurements that use hyperfine-interval-based atomic clocks, scheme discussed here is model independent and does not require separation different physical constants. The possibility applying zero-differential-Stark-shift lattice technique explored measure vibrational transitions at high accuracy.
Aided by ultra-high resolution spectroscopy, the overall systematic uncertainty of $^{1}S_{0}$-$^{3}P_{0}$ clock resonance for lattice-confined $^{87}$Sr has been characterized to $9\times10^{-16}$. This is at a level similar Cs-fountain primary standard, while potential stability lattice clocks exceeds that Cs. The absolute frequency transition measured be 429,228,004,229,874.0(1.1) Hz, where $2.5\times10^{-15}$ fractional represents most accurate measurement neutral-atom-based optical date.
With ultracold $^{87}$Sr confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to-date of $^1S_0$ - $^3P_0$ clock transition with detailed analysis systematic shifts (20 absolute frequency measurement 429 228 004 229 867 Hz. The high resolution permits an investigation lattice motional sideband structure. local oscillator for this atomic is stable diode laser its Hz-level linewidth characterized across spectrum using femtosecond comb.
We present a detailed experimental and theoretical study of the effect nuclear spin on performance optical lattice clocks. With state-mixing theory including spin-orbit hyperfine interactions, we describe origin $^{1}S_{0}\text{\ensuremath{-}}^{3}P_{0}$ clock transition differential $g$ factor between two states for alkaline-earth-metal(-like) atoms, using $^{87}\mathrm{Sr}$ as an example. Clock frequency shifts due to magnetic fields are discussed with emphasis those relating structure. An...
The absolute frequency of the 1 S 0 -3 P clock transition 87 Sr has been measured to be 429 228 004 229 873.65 (37) Hz using lattice-confined atoms, where fractional uncertainty 8.6×10 -16 represents one most accurate measurements an atomic date.After a detailed study systematic effects, which reduced total lattice 1.5×10 , is against hydrogen maser simultaneously calibrated US primary standard, NIST Cs fountain clock, NIST-F1.The comparison made possible femtosecond laser based optical comb...
Neutral quantum absorbers in optical lattices have emerged as a leading platform for achieving clocks with exquisite spectroscopic resolution. However, the studies of these and their systematic shifts so far been limited to atoms. Here, we extend this architecture an ensemble diatomic molecules experimentally realize accurate lattice clock based on pure molecular vibration. We evaluate systematics, including characterization nonlinear trap-induced light shifts, total uncertainty...
Highest resolution laser spectroscopy has generally been limited to single trapped ion systems due rapid decoherence which plagues neutral atom ensembles. Here, precision of ultracold atoms confined in a trapping potential shows superior optical coherence without any deleterious effects from motional degrees freedom, revealing resonance linewidths at the hertz level with an excellent signal noise ratio. The quality factor 2.4 x 10^{14} is highest ever recovered form coherent spectroscopy....
Optical frequency combs, coherent light sources that connect optical frequencies with microwave oscillations, have become the enabling tool for precision spectroscopy, clockwork and attosecond physics over past decades. Current benchmark systems are self-referenced femtosecond mode-locked lasers, but four-wave-mixing in high-Q resonators emerged as alternative platforms. Here we report generation full stabilization of CMOS-compatible combs. The spiral microcomb's two degrees-of-freedom, one...
We have produced large samples of stable ultracold (88)Sr(2) molecules in the electronic ground state an optical lattice. The fast, all-optical method molecule creation involves a near-intercombination-line photoassociation pulse followed by spontaneous emission with near-unity Franck-Condon factor. detection uses excitation to weakly bound electronically excited vibrational level corresponding very dimer and yields high-Q molecular vibronic resonance. This is first two steps needed create...
Next-generation wireless communication networks will require powerful, stable sources of electromagnetic radiation operating at terahertz frequencies. A new study demonstrates the feasibility such a source by combing microscale cavity with photomixer.
The Cold molecule Nuclear Time-Reversal EXperiment (CeNTREX) is a new effort aiming for significant increase in sensitivity over the best present upper bounds on strength of hadronic time reversal ($T$) violating fundamental interactions. experimental signature will be shifts nuclear magnetic resonance frequencies $^{205}$Tl electrically-polarized thallium fluoride (TlF) molecules. Here we describe motivation studying these $T$-violating interactions and using TlF to do so. To achieve higher...
Developments in cooling, trapping, and coherent manipulation of molecules allow for precise control their quantum states. Quantum state can enable high-precision measurements, including tests fundamental symmetries searches new physics beyond the Standard Model. This Perspective reviews recent developments this field discusses current future research directions.
We demonstrate optical cycling and sub-Doppler laser cooling of a cryogenic buffer-gas beam calcium monohydride (CaH) molecules. measure vibrational branching ratios for transitions both excited electronic states A B. further that repeated photon scattering via the $A\leftarrow X$ transition is achievable at rate $\sim$ $1.6\times10^6$ photons/s interaction-time limited $200$ photons by repumping largest decay channel. also ability to cool molecular CaH through magnetically assisted Sisyphus...
Abstract When an inverted ensemble of atoms is tightly packed on the scale its emission wavelength or when are collectively strongly coupled to a single cavity mode, their dipoles will align and decay rapidly via superradiant burst. However, spread-out dipole phase distribution theory predicts required minimum threshold atomic excitation for superradiance occur. Here we experimentally confirm this predicted narrow optical transition exciting transversely show how take advantage resulting...
The aim of CeNTREX (Cold Molecule Nuclear Time-Reversal Experiment) is to search for time-reversal symmetry violation in the thallium nucleus, by measuring Schiff moment $^{205}$Tl polar molecule fluoride (TlF). uses a cryogenic beam TlF with rotational temperature 6.3(2) K. This results population spread over dozens and hyperfine sublevels TlF, while only single level useful measurement. Here we present protocol cooling degrees freedom beam, transferring majority Boltzmann distribution into...
Cryogenic buffer gas sources are ubiquitous for producing cold, collimated molecular beams quantum science, chemistry, and precision measurements. The molecules typically produced by laser ablating a metal target in the presence of donor gas, where radical interest emerges among reaction products due to barrier-free process or under thermal optical excitation. High-barrier reactions, such as between calcium hydrogen, should be precluded. Here, we study chemical reactions Ca three hydrogen...
With ultracold 88Sr in a 1D magic wavelength optical lattice, we performed narrow-line photoassociation spectroscopy near the 1S0 - 3P1 intercombination transition. Nine least-bound vibrational molecular levels associated with long-range 0u and 1u potential energy surfaces were measured identified. A simple theoretical model accurately describes level positions treats effects of lattice confinement on line shapes. The resonance strengths show that tuning ground state scattering length should...
We present the first experimental demonstration of radiation pressure force deflection and direct laser cooling for barium monohydride (BaH) molecules resulting from multiple photon scattering. Despite a small recoil velocity (2.7 mm/s) long excited state lifetime (137 ns), we use 1060 nm light exciting $X\rightarrow A$ electronic transition BaH to deflect cryogenic buffer-gas beam reduce its transverse spread. Multiple methods are employed characterize optical cycling dynamics benchmark...
The three 2(3)P fine structure intervals of 4H are measured at an improved accuracy that is sufficient to test two-electron QED theory and determine the constant alpha 14 parts in 10(9). more accurate determination alpha, a precision higher than attained with quantum Hall Josephson effects, awaits reconciliation two inconsistent theoretical calculations now being compared term by term. A low pressure helium discharge presents experimental uncertainties quite different for earlier...