Prof. Debayan Mitra, Indiana University Bloomington

Molecular Advantage for Quantum Science Applications

In recent years, cold and ultracold molecules have emerged as a mature platform for quantum simulation, computation, chemistry and precision measurements. Molecules provide unique features and challenges compared to their atomic analogs. In this talk, I will discuss two avenues where molecular advantage plays a key role. First, I will discuss how the molecules CaH and CaD can be used as a vehicle to produce ultracold and trapped hydrogen and deuterium atoms for precision measurement. I will discuss the process of formation of the molecules CaH and CaD and our latest efforts towards laser cooling it. Second, I will talk about the planned pathway to building a quantum gas microscope of laser cooled fermionic molecules with tunable long-range interactions. I will describe how the molecule MgF possesses many of the properties favorable to both laser cooling and single-site imaging. I will also discuss some of the challenges posed by this new class of molecules with UV transitions.

Prof. Luca Argenti, University of Central Florida

ASTRA: A Transition-Density-Matrix Approach to Time-Resolved Molecular Ionization

Attosecond science, which investigates the time-resolved correlated motion of electrons in atoms, molecules, and solids, is rapidly advancing toward larger molecular systems and more complex processes, such as multiple ionization and molecular fragmentation. Theoretical methods capable of addressing both multiple excitations and photofragment entanglement are essential to capture these phenomena. Among the most promising theoretical approaches are ab initio wave-function-based close-coupling (CC) methods, increasingly adopted by the AMO community.

Despite significant progress from codes like XCHEM [1,2], tRecX [3], RMT [4], and UKRmol+ [5], scaling remains a major challenge – whether in handling ionic correlation, accounting for many atoms, or for distant fragments. To address these limitations, we developed ASTRA [6] (AttoSecond TRAnsitions), an ab initio CC molecular ionization code based on high-order transition density matrices between correlated ionic states of arbitrary multiplicity [7], and hybrid Gaussian-B-spline integrals [5,9]. ASTRA integrates multiple state-of-the-art codes, such as DALTON [8], a general-purpose quantum chemistry code, LUCIA [7], a large-scale CI code, and GBTOlib [5], a hybrid integral library suited for slow photoelectrons and comparatively small molecules.

ASTRA has successfully reproduced total and partial photoionization cross sections, photoemission asymmetry parameters, and molecular-frame photoelectron angular distributions for molecules such as N ₂ , CO, H ₂ CO, and Pyrazine, showing excellent agreement with existing benchmarks. Currently, ASTRA is being applied to study attosecond transient absorption spectra of CO and O ₂ , as well as sequential XUV-pump IR-probe ionization of C ₂ H ₄ . Its formalism naturally extends to molecular double ionization and can efficiently model electron exchange between multiple disjoint molecular fragments − relevant for describing ionization in weakly bound clusters like (H ₂ O) _n .

Looking ahead, continued integration with tools tailored to high-energy photoemission, non-adiabatic nuclear dynamics, and strong fields ionization will be critical for addressing emerging challenges in ultrafast many-body dynamics. Free-electron lasers enable time-resolved studies of core ionization, while table-top attosecond pump-probe experiments are targeting increasingly larger molecules, monitoring both electron dynamics and nuclear rearrangements throughout chemical reactions with intense probe pulses [10]. To reproduce these complex experiments, we are collaborating with NIST to replace GBTOlib with a more efficient hybrid library capable of handling larger molecules and higher orbital angular momenta. We are also pairing ASTRA with surface-hopping methods [11], where multiphoton ionization is typically not available. Additionally, to track the asymptotic evolution of weakly coupled photofragments under strong light fields − without incurring prohibitive computational costs − we are considering integrating separate optimized propagators for each fragment, which will open the door for us to simulate strong-field multichannel molecular-ionization processes.

[1] M. Klinker et al., J. Phys. Chem. Lett. 9, 756 (2018).

[2] V. J. Borràs et al., Science Advances 9, eade3855 (2023).

[3] A. Scrinzi, Comput. Phys. Commun. 270, 108146 (2022).

[4] A. C. Brown et al., Comput. Phys. Commun. 250, 107062 (2020).

[5] Z. Masin et al., Comp. Phys. Commun. 249, 107092 (2020).

[6] J. M. Randazzo et al., Phys. Rev. Res. 5, 043115 (2023).

[7] J. Olsen et al., J. Chem. Phys. 89, 2185 (1988); ibid. 104, 8007 (1996).

[8] K. Aidas et al., Comp. Mol. Sci. 4, 269 (2014).

[9] H. Gharibnejad et al., Comp. Phys. Commun. 263, 107889 (2021).

[10] F. Vismarra et al., Nature Chemistry (2024).

[11] L. Fransén et al., J. Phys. Chem. A 128, 1457 (2024).

Prof. Bryce Gadway, Penn State

Synthetic Dimensions in Rydberg Atom Array

Arrays of dipolar-interacting spins - magnetic atoms, polar molecules, and Rydberg atoms - represent powerful and versatile platforms for analog quantum simulation experiments. The internal state dynamics in these dipolar arrays provide a natural setting to explore problems of equilibrium and non-equilibrium quantum magnetism. The presence of many internal states of the atoms and molecules further enables studies of large-spin magnetism, but also holds promise for more general quantum simulation studies. Here we describe how the simple addition of multi-frequency microwave fields to Rydberg arrays enables highly controllable studies of few- and many-body dynamics along an internal-state “synthetic” dimension. I’ll discuss several early studies in the Rydberg synthetic dimension platform, touching on interaction-driven phenomena relevant to topology, artificial gauge fields, and disorder-induced localization. Looking forward, such microwave manipulation opens up several new directions for exploring complex, driven quantum matter in dipolar arrays.

Prof. Wenchao Ge, University of Rhode Island

How to Make a Faster Trapped-Ion Quantum Computer?

Trapped ions offer a pristine platform for quantum computation, but enhancing the interactions without compromising the qubits remains a crucial challenge. In this talk, I will present a strategy to enhance the interaction strengths in trapped-ion systems via parametric amplification of the ions’ motion, thereby suppressing the relative importance of decoherence. We illustrate the power of this approach by showing how it can improve the speed and fidelity of two-qubit gates in multi-ion systems and how it can enhance collective spin states useful for quantum metrology. Our proposal has been further demonstrated in the experiment, confirming the enhancement. Our results open a new avenue of phonon modulation in trapped ions and are directly relevant to numerous other physical platforms in which spin interactions are mediated by bosons.

Jake Lewitt, Cortex Fusion, New York, NY

Nuclear fusion in molecules using lasers

Cortex Fusion Systems, Inc. uses shaped ultrafast laser pulses to catalyze fusion reactions in molecules. Our work comprises (1) designing transiently confining effective one-electron potentials in field-dressed molecules, (2) performing quantum chemistry calculations to validate the enhancement of nuclear tunneling by laser-modified electron screening dynamics, and (3) testing pulse shapes in the laser lab by coupling ultrafast spectroscopy techniques with nuclear radiation detection and spectrometry. In this regard, “quantum-controlled fusion” is a coherent, under-the-barrier process that does not require plasma ignition. Our goal is to repurpose the modern suite of commercial femtosecond laser amplifiers and pulse-shaping techniques to achieve compact and scalable fusion generators using quantum control.

Dr. Zeyang Li, Stanford University

Applying Cavity QED to Quantum Information Science

Abstract TBA