2024 New's Items

An efficient quantum algorithm for generation of ab initio n-th order susceptibilities for non-linear spectroscopies

Kharazi, T.
Stetina, T. F.
Ko, L.
Low, G. H.
Whaley, K. B.
2024

We develop and analyze a fault-tolerant quantum algorithm for computing n-th order response properties necessary for analysis of non-linear spectroscopies of molecular and condensed phase systems. We use a semi-classical description in which the electronic degrees of freedom are treated quantum mechanically and the light is treated as a classical field. The algorithm we present can be viewed as an implementation of standard perturbation theory techniques, focused on ab initio calculation of n-th order response functions. We provide cost estimates in terms of the number of queries to the...

ML-Powered FPGA-based Real-Time Quantum State Discrimination Enabling Mid-circuit Measurements

Vora, N. R.
Xu, Y.
Hashim, A.
Fruitwala, N.
Nguyen, H. N.
Liao, H.
Balewski, J.
Rajagopala, A.
Nowrouzi, K.
Ji, Q.
Whaley, K. B.
Siddiqi, I.
Nguyen, P.
Huang, G.
2024

Similar to reading the transistor state in classical computers, identifying the quantum bit (qubit) state is a fundamental operation to translate quantum information. However, identifying the qubit state has been the slowest and most susceptible to errors operation on superconducting quantum processors. Most existing qubit state discriminating algorithms have only been implemented and optimized “after the fact”—using offline data transferred from a quantum control circuit to host computers. Real-time state discrimination is not possible because a superconducting qubit state only survives...

The surface chemistry of colloidal lead halide perovskite nanowires

Oddo, A. M.
Arnold, M.
Yang, P.
2024

This study explored the interplay between the ligand–surface chemistry of colloidal CsPbBr3 nanowires (NWs) and their optical properties. The ligand equilibrium was probed using nuclear magnetic resonance spectroscopy, and by perturbing the equilibrium via dilution, the gradual removal of ligands from the CsPbBr3 surface was observed. This removal was correlated with an increase in the surface defect density, as suggested by a broadening of the photoluminescence (PL) spectrum, a decrease in the PL quantum yield (PLQY), and quenching of...

Performance of wave function and Green's functions based methods for non equilibrium many-body dynamics

Reeves, C. C.
Harsha, G.
Shee, A.
Zhu, Y.
Blommel, T.
Yang, C.
Whaley, K. B.
Zgid, D.
Vlček, V.
2024

Theoretical descriptions of the non-equilibrium dynamics of quantum many-body systems essentially employ either (i) explicit treatments, relying on the truncation of the expansion of the many-body wavefunction, (ii) compressed representations of the many-body wavefunction, or (iii) evolution of an effective (downfolded) representation through Green’s functions. In this work, we select representative cases of each of the methods and address how these complementary approaches capture the dynamics driven by intense field perturbations to non-equilibrium states. Under strong driving, the...

Explicit block encodings of boundary value problems for many-body elliptic operators

Kharazi, T.
Alkadri, A. M.
Liu, J.-P.
Mandadapu, K. K.
Whaley, K. B.
2024

Simulation of physical systems is one of the most promising use cases of future digital quantum computers. In this work we systematically analyze the quantum circuit complexities of block encoding the discretized elliptic operators that arise extensively in numerical simulations for partial differential equations, including high-dimensional instances for many-body simulations. When restricted to rectangular domains with separable boundary conditions, we provide explicit circuits to block encode the many-body Laplacian with separable periodic, Dirichlet, Neumann, and Robin boundary...

Machine Learned Potential for High-Throughput Phonon Calculations of Metal-Organic Frameworks

Elena, A. M.
Kamath, P. D.
Inizan, T. J.
Rosen, A. S.
Zanca, F.
Persson, K. A.
2025

Metal–organic frameworks (MOFs) are highly porous and versatile materials studied extensively for applications such as carbon capture and water harvesting. However, computing phonon-mediated properties in MOFs, like thermal expansion and mechanical stability, remains challenging due to the large number of atoms per unit cell, making traditional Density Functional Theory (DFT) methods impractical for high-throughput screening. Recent advances in machine learning potentials have led to foundation atomistic models, such as MACE-MP-0, that accurately predict equilibrium structures but struggle...

Mechanochemically accelerated deconstruction of chemically recyclable plastics

Hua, M.
Peng, Z.
Guha, R. D.
Ruan, X.
Ng, K. C.
Demarteau, J.
Haber, S.
Fricke, S. N.
Reimer, J. A.
Salmeron, M. B.
Persson, K. A.
Wang, C.
Helms, B. A.
2024
Plastics redesign for circularity has primarily focused on monomer chemistries enabling faster deconstruction rates concomitant with high monomer yields. Yet, during deconstruction, polymer chains interact with their reaction medium, which remains underexplored in polymer reactivity. Here, we show that, when plastics are deconstructed in reaction media that promote swelling, initial rates are accelerated by over sixfold beyond those in small-molecule analogs. This unexpected acceleration is primarily tied to mechanochemical activation of strained polymer chains; however, changes in the...

The Interplay Between Electron Localization, Magnetic Order, and Jahn-Teller Distortion that Dictates LiMnO2 Phase Stability

Ronald L. Kam
Luca Binci
Aaron D. Kaplan
Kristin A. Persson
Nicola Marzari
Gerbrand Ceder
2024

The development of manganese (Mn)-rich cathodes for Li-ion batteries promises to alleviate potential supply chain bottlenecks in battery manufacturing. Fundamental challenges in Mn-rich cathodes arise from phenomena such as structural changes due to cooperative Jahn-Teller (JT) distortions of Mn3+ in octahedral environments, Mn migration, and phase transformations to spinel-like order, all of which affect the electrochemical performance. These physically complex phenomena motivate an ab initio re-examination of the Li-Mn-O rock-salt space, with a focus on the thermodynamics of the...

Synchronized states in a ring of dissipatively coupled harmonic oscillators

Moreno JN
Wächtler CW
Eisfeld A
2024

The question under which conditions oscillators with slightly different frequencies synchronize appears in various settings. We consider the case of a finite number of harmonic oscillators arranged on a ring, with bilinear, dissipative nearest-neighbor coupling. We show that by tuning the gain and loss appropriately, stable synchronized dynamics may be achieved. These findings are interpreted using the complex eigenvalues and eigenvectors of the non-Hermitian matrix describing the dynamics of the system. We provide a complete discussion for the case of two oscillators. Ring sizes...

Engineering interlayer hybridization in van der Waals bilayers

Barré, E.
Dandu, M.
Kundu, S.
Sood, A.
da Jornada, F. H.
Raja, A.
2024

In the decade since the introduction of van der Waals (vdW) heterostructures for designer devices, there has been an abundance of studies on the artificial assembly of vdW heterostructures for light–matter interactions, charge and energy transport, and other condensed matter phenomena. The interlayer interactions or hybridization in these systems non-trivially impact their physical characteristics and are sensitive to a complex set of interdependent, externally tunable parameters. There lacks a coherent perspective on how these external stimuli can be used together to engineer materials...