arXiv subjects

Eric A. Cornell

Publications and source records attributed to Eric A. Cornell.

30 records · Page 2Linked to original sources

arXiv2012

Broadband velocity modulation spectroscopy of HfF^+: towards a measurement of the electron electric dipole moment

Precision spectroscopy of trapped HfF^+ will be used in a search for the permanent electric dipole moment of the electron (eEDM). While this dipole moment has yet to be observed, various extensions to the standard model of particle physics (such as supersymmetry) predict values that are close to the current limit. We present extensive survey spectroscopy of 19 bands covering nearly 5000 cm^(-1) using both frequency-comb and single-frequency laser velocity-modulation spectroscopy. We obtain high-precision rovibrational constants for eight electronic states including those that will be necessary for state preparation and readout in an actual eEDM experiment.

physics.atom-ph↗

arXiv2012

REMPI Spectroscopy of HfF

The spectrum of electronic states at 30000--33000 cm$^{-1}$ in hafnium fluoride has been studied using (1+1) resonance-enhanced multi-photon ionization (REMPI) and (1+1$'$) REMPI. Six $Ω' = 3/2$ and ten $Π_{1/2}$ vibronic bands have been characterized. We report the molecular constants for these bands and estimate the electronic energies of the excited states using a correction derived from the observed isotope shifts. When either of two closely spaced $Π_{1/2}$ electronic states is used as an intermediate state to access autoionizing Rydberg levels, qualitatively distinct autoionization spectra are observed. The intermediate state-specificity of the autoionization spectra bodes well for the possibility of using a selected $Π_{1/2}$ state as an intermediate state to create ionic HfF$^+$ in various selected quantum states, an important requirement for our electron electric dipole moment (eEDM) search in HfF$^+$.

physics.chem-ph↗

arXiv2012

Near-infrared LIF spectroscopy of HfF

The molecular ion HfF$^+$ is the chosen species for a JILA experiment to measure the electron electric dipole moment (eEDM). Detailed knowledge of the spectrum of HfF is crucial to prepare HfF$^+$ in a state suitable for performing an eEDM measurement\cite{Leanhardt}. We investigated the near-infrared electronic spectrum of HfF using laser-induced fluorescence (LIF) of a supersonic molecular beam. We discovered eight unreported bands, and assign each of them unambiguously, four to vibrational bands belonging to the transition $[13.8]0.5 \leftarrow X1.5$, and four to vibrational bands belonging to the transition $[14.2]1.5 \leftarrow X1.5$. Additionally, we report an improved measurement of vibrational spacing of the ground state, as well as anharmonicity $ω_e x_e$.

physics.atom-ph↗

arXiv2011

Laser-induced fluorescence studies of HfF+ produced by autoionization

Autoionization of Rydberg states of HfF, prepared using the optical-optical double resonance (OODR) technique, holds promise to create HfF+ in a particular Zeeman level of a rovibronic state for an electron electric dipole moment (eEDM) search. We characterize a vibronic band of Rydberg HfF at 54 cm-1 above the lowest ionization threshold and directly probe the state of the ions formed from this vibronic band by performing laser-induced fluorescence (LIF) on the ions. The Rydberg HfF molecules show a propensity to decay into only a few ion rotational states of a given parity and are found to preserve their orientation qualitatively upon autoionization. We show empirically that we can create 30% of the total ion yield in a particular |J+,M+> state and present a simplified model describing autoionization from a given Rydberg state that assumes no angular dynamics.

physics.atom-ph↗

arXiv2011

On Measuring the Electron Electric Dipole Moment in Trapped Molecular Ions

Trapped diatomic molecular ions could prove to be a sensitive probe for a permanent electron electric dipole moment (eEDM). We propose to use a ground or metastable $^3Δ_1$ level, due to its high polarizability and large EDM enhancement factor. Ions allow for simple trapping and long interrogation times, but require a time-varying electric bias field in order to probe the eEDM. We discuss experimental design as well as challenges in performing a precision spectroscopic measurement in rapidly time-varying electric fields.

physics.atom-ph↗

arXiv2011

Frequency Comb Velocity-Modulation Spectroscopy

We have demonstrated a new technique that provides massively parallel comb spectroscopy sensitive specifically to ions through the combination of cavity-enhanced direct frequency comb spectroscopy with velocity modulation spectroscopy. Using this novel system, we have measured electronic transitions of HfF+ and achieved a fractional absorption sensitivity of 3 x 10-7 recorded over 1500 simultaneous channels spanning 150 cm-1 around 800 nm with an absolute frequency accuracy of 30 MHz (0.001 cm-1). A fully sampled spectrum consisting of interleaved measurements is acquired in 30 minutes.

physics.atom-ph↗

arXiv2010

Revealing buried information: Statistical processing techniques for ultracold gas image analysis

The techniques of principal and independent component analysis are applied to images of ultracold atoms. As an illustrative example, we present the use of these model-independent methods to rapidly determine the differential phase of a BEC interferometer from large sets of images of interference patterns. These techniques have been useful in the calibration of the experiment and in the investigation of phase randomization. The details of the algorithms are provided.

physics.atom-ph↗

arXiv2004

An Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate

An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with atom propagation time of 10 ms.

cond-mat.other↗

arXiv2001

Dynamics of collapsing and exploding Bose-Einstein condensates

We explored the dynamics of how a Bose-Einstein condensate collapses and subsequently explodes when the balance of forces governing the size and shape of the condensate is suddenly altered. A condensate's equilibrium size and shape is strongly affected by the inter-atomic interactions. Our ability to induce a collapse by switching the interactions from repulsive to attractive by tuning an externally-applied magnetic field yields a wealth of detailed information on the violent collapse process. We observe anisotropic atom bursts that explode from the condensate, atoms leaving the condensate in undetected forms, spikes appearing in the condensate wave function, and oscillating remnant condensates that survive the collapse. These all have curious dependencies on time, the strength of the interaction, and the number of condensate atoms. Although ours would seem to be a simple well-characterized system, our measurements reveal many interesting phenomena that challenge theoretical models.

cond-mat.stat-mech↗

arXiv2000

A waveguide atom beamsplitter for laser-cooled neutral atoms

A laser-cooled neutral-atom beam from a low-velocity intense source is split into two beams while guided by a magnetic-field potential. We generate our multimode-beamsplitter potential with two current-carrying wires on a glass substrate combined with an external transverse bias field. The atoms bend around several curves over a $10$-cm distance. A maximum integrated flux of $1.5\cdot10^{5} \mathrm{atoms/s}$ is achieved with a current density of $5\cdot10^{4} \mathrm{Ampere/cm^{2}}$ in the 100-$\mathrm{μm}$ diameter wires. The initial beam can be split into two beams with a 50/50 splitting ratio.

physics.atom-ph↗

arXiv1999

Guiding neutral atoms around curves with lithographically patterned current-carrying wires

Laser-cooled neutral atoms from a low-velocity atomic source are guided via a magnetic field generated between two parallel wires on a glass substrate. The atoms bend around three curves, each with a 15-cm radius of curvature, while traveling along a 10-cm-long track. A maximum flux of 2*10^6 atoms/sec is achieved with a current density of 3*10^4 A/cm^2 in the 100x100-micrometer-cross-section wires. The kinetic energy of the guided atoms in one transverse dimension is measured to be 42 microKelvin.

physics.atom-ph↗

arXiv1999

Experiments in Dilute Atomic Bose-Einstein Condensation

Both theoretical and experimental activity in BEC has expanded dramatically in the three years since the first observation of BEC in a dilute atomic gas. One is tempted to ask, why? Why is there so much interest in the field? Is this burst of activity something that could have been foreseen, in, say, 1990?

cond-mat↗