Compared to purely atomic collisions, ultracold molecular collisions potentially support a much larger number of Fano-Feshbach resonances due the enormous rovibrational states available. In fact, for alkali-metal dimers we find that resulting density cannot be resolved at all, even on sub-$\ensuremath{\mu}$K temperature scale experiments. As result, all observables become averaged over many and can effectively described by simpler, nonresonant scattering calculations. Two particular examples...

Compared to purely atomic collisions, ultracold collisions involving molecules have the potential support a much larger number of Fano-Feshbach resonances due huge amount ro-vibrational states available. In order handle such atom-molecule we formulate theory that incorporates in statistical manner while treating physics long-range scattering, which is sensitive things as hyperfine states, collision energy, and any applied electromagnetic fields, exactly within multichannel quantum defect...

Tracking a trio of rubidium atoms Crossed molecular beams have provided decades' worth knowledge into how quantum mechanics governs chemical reactivity. Nonetheless, the technique is generally limited to collision two partners. Wolf et al. report on three-body process with full state resolution. By cooling ultralow temperatures in an optical trap, they were able observe dimer formation, stabilized by third atom, and extract precise dependence product states initial involved. Science , this...

Abstract Experiments with trapped ions and neutral atoms typically employ optical modulators in order to control the phase, frequency, amplitude of light directed individual atoms. These elements are expensive, bulky, consume substantial power, often rely on free-space I/O channels, all which pose scaling challenges. To support many-ion systems like trapped-ion quantum computers or miniaturized deployable devices clocks sensors, these must ultimately be microfabricated, ideally...

We introduce a choice of reference wave functions that allows multichannel quantum defect theory (MQDT) to describe ultracold collisions involving high-partial-wave numbers $L$. This requires careful standardization the MQDT at long range ensure their linear independence. To illustrate simplicity and accuracy resulting theory, we perform comprehensive calculation $L\ensuremath{\le}2$ Fano-Feshbach resonances in $0--1000$ G for scattering ${}^{40}\mathrm{K}{+}^{87}\mathrm{Rb}$ lowest...

A simple Penning ion generator (PIG) that can be easily fabricated with machining skills and standard laboratory accessories is described. The PIG source uses an iron cathode body, samarium cobalt permanent magnet, stainless steel anode, faceplate to generate a plasma discharge yields continuous 1 mA beam of positively charged hydrogen ions at mTorr pressure. This operating condition requires 5.4 kV 32.4 W power. Operation helium similar hydrogen. being designed investigated for use in...

We demonstrate the emergence of universal Efimov physics for interacting photons in cold gases Rydberg atoms. consider behavior three injected into gas their propagating frame, where a paraxial approximation allows us to them as massive particles. In contrast atoms and nuclei, have large anisotropy between longitudinal mass, arising from dispersion, transverse diffraction. Nevertheless, we show that, suitably rescaled coordinates, effective interactions become dominated by s-wave scattering...

We provide a comprehensive comparison of coupled channels calculation, the asymptotic bound state model (ABM), and multichannel quantum defect theory (MQDT). Quantitative results for $^6$Li -$^{133}$Cs are presented compared to previously measured Feshbach resonances (FRs) [M. Repp et al., Phys. Rev. A 87 010701(R) (2013)]. demonstrate how accuracy ABM can be stepwise improved by including magnetic dipole-dipole interactions coupling non-dominant virtual state. present MQDT where second...

We present a formalism for cold and ultracold atom-diatom chemical reactions that combines quantum close-coupling method at short-range with defect theory long-range. The yields full state-to-state rovibrationally resolved cross sections as in standard (CC) calculations but considerably less computational expense. This hybrid approach exploits the simplicity of MQDT while treating interaction explicitly using CC calculations. method, demonstrated D+H$_2\to$ HD+H collisions rovibrational...

One of the many challenges developing an open user testbed such as QSCOUT is providing interface that maintains simplicity without compromising expressibility or control. This comprises two distinct elements: a quantum assembly language designed for specifying circuits at gate level, and low-level counterpart used describing gates in terms waveforms realize specific operations. Jaqal, "Just another language," gate-level descriptions circuits. JaqalPaw, "Jaqal pulses waveforms," its...

Recent progress in generating entangled spin states of neutral atoms provides opportunities to advance quantum sensing technology. In particular, entanglement can enhance the performance accelerometers and gravimeters based on light-pulse atom interferometry. We study effects error sources that may limit sensitivity such devices, including errors preparation initial state, imperfections laser pulses, momentum spread atomic wave packet, measurement errors, spontaneous emission, loss....

Multichannel quantum defect theory (MQDT) has been widely applied to resonant and non-resonant scattering in a variety of atomic collision processes. In recent years, the method cold collisions with considerable success, it proven be computationally viable alternative full-close coupling (CC) calculations when spin, hyperfine external field effects are included. this paper, we describe hybrid approach for molecule-molecule that includes simplicity MQDT while treating short-range interaction...

Entangling gates in trapped-ion quantum computers are most often applied to stationary ions with initial motional distributions that thermal and close the ground state, while those demonstrations involve transport generally use sympathetic cooling reinitialize state prior applying a gate. Future systems more ions, however, will face greater nonthermal excitation due increased amounts of ion exacerbated by longer operational times variations over trap array. In addition, pregate may be...

Spectroscopic measurements are made and obtained for three molecular levels within 50 MHz of the atomic continuum, along with their variation magnetic field in ultracold 40K Fermi gases. We use spectroscopic to modify scattering properties near Fano–Feshbach resonances a radio-frequency (RF) by measuring loss profile versus field. This work provides high accuracy locations ground states s-wave resonance, which can be used study crossover regime from Bose–Einstein condensate...

Using new experimental measurements of photoassociation resonances near the $^1\mathrm{S}_0 \rightarrow \phantom{ }^3\mathrm{P}_1$ intercombination transition in $^{84}$Sr and $^{86}$Sr, we present an updated study into mass-scaling behavior bosonic strontium dimers. A previous model [Borkowski et al., Phys. Rev. 90, 032713 (2014)] was able to incorporate a large number for $^{88}$Sr, but at time only handful close dissociation limit were known $^{86}$Sr. In this work, perform more thorough...

Current noisy intermediate-scale quantum (NISQ) trapped-ion devices are subject to errors which can significantly impact the accuracy of calculations if left unchecked. A form error mitigation called zero noise extrapolation (ZNE) decrease an algorithm's sensitivity these without increasing number required qubits. Here, we explore different methods for integrating this technique into Variational Quantum Eigensolver (VQE) algorithm calculating ground state HeH+ molecule at 0.8 Angstrom in...

Fully understanding a chemical reaction on the quantum level is long-standing goal in physics and chemistry. Experimental investigation of such state-to-state chemistry requires both preparation reactants detection products state resolved way, which has been long term challenge. Using high control ultracold domain, we prepare few-body demonstrate with unprecedented resolution. We present measurements accompanying theoretical analysis for recombination three spin-polarized Rb atoms forming...

In this work, we design and implement frequency-robust Molmer-Sorensen gates on a linear chain of trapped ions, using Gaussian amplitude modulation constant laser frequency. We select frequency to balance the entanglement accumulation all motional modes during gate produce strong robustness error, even for long ion chains. demonstrate technique three-ion chain, achieving $<\,1\%$ reduction from peak fidelity over $20\,$kHz range offset, analyze performance through numerical simulations...