Raphael Levine

• University of California, Los Angeles

Atto pulses allow controlling the charge migration and the spatio-temporal beating of the electronic density on a purely electronic time scale by tailoring the parameters of the pump pulse to excite specific electronic coherences. As the nuclei begin to move, the electronic and nuclear motions are entangled and the engineered electronic coherences...

Nonadiabatic quantum dynamics sheds light on the non-monotonic energy dependence of the branching fractions of N 2 .

The Hamiltonian of a quantum system governs the dynamics of the system via the Schrodinger equation. In this paper, the Hamiltonian is reconstructed in the Pauli basis using measurables on random states forming a time series data set. The time propagation is implemented through Trotterization and optimized variationally with gradients computed on t...

A quantum machine that accepts an input and processes it in parallel is described. The logic variables of the machine are not wavefunctions (qubits) but observables (i.e., operators) and its operation is described in the Heisenberg picture. The active core is a solid-state assembly of small nanosized colloidal quantum dots (QDs) or dimers of dots....

The Hamiltonian of a quantum system governs the dynamics of the system via the Schrodinger equation. In this paper, the Hamiltonian is reconstructed in the Pauli basis using measurables on random states forming a time series dataset. The time propagation is implemented through Trotterization and optimized variationally with gradients computed on th...

Quantum state tomography is an integral part of quantum computation and offers the starting point for the validation of various quantum devices. One of the central tasks in the field of state tomography is to reconstruct, with high fidelity, the quantum states of a quantum system. From an experiment on a real quantum device, one can obtain the mean...

Ultrafast pumping displaces both electrons and nuclei from equilibrium so that the wave function is a double sum of separable terms for the dynamics of the electrons and nuclei. We convert the double sum into a single one by a matricization of the wave function and then generate an exact separable expression for the entangled molecular wave functio...

Quantum state tomography is an integral part of quantum computation and offers the starting point for the validation of various quantum devices. One of the central tasks in the field of state tomography is to reconstruct with high fidelity, the quantum states of a quantum system. From an experiment on a real quantum device, one can obtain the mean...

We report a preliminary step in the application of information theory motivated surprisal analysis to irreversible processes but having linear equations of motion. Here we aim to describe the dynamics of varied Smoluchowski diffusion processes. In surprisal analysis, the probability density over the sample space is written as an exponential functio...

Impressive progress has been made in the past decade in the study of technological applications of varied types of quantum systems. With industry giants like IBM laying down their roadmap for scalable quantum devices with more than 1000-qubits by the end of 2023, efficient validation techniques are also being developed for testing quantum processin...

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices are noisy intermediate-scale quantum devices, and so approaches to validate quantum processing on these quantu...

Non-invasively probing metabolites within single live cells is highly desired but challenging. Here we utilize Raman spectro-microscopy for spatial mapping of metabolites within single cells, with the specific goal of identifying druggable metabolic susceptibilities from a series of patient-derived melanoma cell lines. Each cell line represents a d...

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices are noisy intermediate-scale quantum $($NISQ$)$ devices, and so approaches to validate quantum processing on t...

Significance There is a worldwide effort toward quantum technology. Information processing, sensing, communication, and related areas are getting much of the attention. The advantages offered by the quantum domain are well recognized and acclaimed. Proposed implementations rely on systems operating at rather low temperatures and on the need to isol...

p>Integrated proteomic and metabolic single-cell assays reveal multiple independent adaptive responses to drug tolerance in a BRAF-mutant melanoma cell line Cancers commonly develop resistance against chemotherapeutics or targeted therapies through various types of genetic or non-genetic mechanisms. Non-genetic mechanisms have been shown to occur...

The determination of individual cell trajectories through a high-dimensional cell-state space is an outstanding challenge for understanding biological changes ranging from cellular differentiation to epigenetic responses of diseased cells upon drugging. We integrate experiments and theory to determine the trajectories that single BRAFV600E mutant m...

A Franck-Condon type argument, which requires the least transfer of momenta to tie nuclei during a collision is out-lined applied to the analysis of transitional energy disposal and its dependence on the initial transitional energy. Using the maximal entropy procedure of information theory we are able to proceed directly from the assumed (model) co...

The thermodynamic limitations on the efficiency of lasers are considered with special reference to operation at a time gain. An entropy cycle is used to determine the thermodynamics threshold condition and to limit the entropy generated during lasing at a finite gain. A lower limit for the required number density of systems in the lasing level is d...

The determination of individual cell trajectories through a high-dimensional cell-state space is an outstanding challenge, with relevance towards understanding biological changes ranging from cellular differentiation to epigenetic (adaptive) responses of diseased cells to drugging. We report on a combined experimental and theoretic method for deter...

The determination of individual cell trajectories through a high-dimensional cell-state space is an outstanding challenge, with relevance towards understanding biological changes ranging from cellular differentiation to epigenetic (adaptive) responses of diseased cells to drugging. We report on a combined experimental and theoretic method for deter...

We resolved a mechanism connecting tumor epigenetic plasticity with non-genetic adaptive resistance to therapy, with MAPK inhibition of BRAF-mutant melanomas providing the model. These cancer cells undergo multiple, reversible drug-induced cell-state transitions, ultimately yielding a drug-resistant mesenchymal-like phenotype. A kinetic series of t...

Cancers commonly develop resistance against chemotherapeutics or targeted therapies through either genetic mechanism or adaptive responses that commonly involve epigenetic reprogramming and activation of compensatory signaling pathways. Recent examples of such an adaptive response involve the treatment of BRAF mutant melanoma cancer patients with i...

Intercommunication between dynamic chemical networks plays a major role in cellular transformations. Inspired by nature, we introduce the intercommunication between two constitutional dynamic networks, CDNs, “S” and “T” composed, each, of four equilibrated supramolecular constituents AA′, AB′, BA′, and BB′, and of CC′, CD′, DC′, and DD′, respective...

Invited by the editorial committee of the Annual Review of Physical Chemistry to "contribute my autobiography," I present it here, as I understand the term. It is about my parents, my mentors, my coworkers, and my friends in learning and the scientific problems that we tried to address. Courtesy of the editorial assistance of Annual Reviews, some o...

We examine computationally how ultrashort polarized strong one cycle IR pulses can be used for steering coherent nuclear dynamics in LiH. The nuclear motion is described using the time-dependent Schrödinger equation on a grid for several coupled electronic states. The coupling to the strong field of the pump and probe pulses is included in the Hami...

The coupled electronic-nuclear coherent dynamics induced by a short strong VUV fs pulse in the low excited electronic states of HCN is probed by transient absorption spectroscopy with a second weaker fs UV pulse. The nuclear time-dependent Schroedinger equation is solved on a 2D nuclear grid with several electronic states with a Hamiltonian includi...

Despite impressive initial response of BRAF targeted therapy in mestastic melanoma patients, acquired drug resistance, often times derived from tumor heterogeneity, always limit its clinical outcome. A dedifferentiation process named melanocyte to neural crest transition (MNT) has shown to be critical in the early stage resistance development. The...

We seek to address fundamental questions in cancer biology by an experimental-theoretical approach based on physicochemical laws. We have recently pioneered the application of the thermodynamic-based surprisal analysis, which has been previously applied to systems in chemistry and physics, to biological processes. We have shown that through the acc...

Dynamical computations demonstrate considerable selectivity over the fragmentation channels of the LiH molecule via the polarization and the carrier envelope phase (CEP) of a single ultrashort one-cycle strong IR pulse. For aligned molecules, control of the CEP allows building nonstationary coherent electronic wave packets of contrasting ionic char...

We consider here multivariate data which we understand as the problem where each data point i is measured for two or more distinct variables. In a typical situation there are many data points i while the range of the different variables is more limited. If there is only one variable then the data can be arranged as a rectangular matrix where i is t...

The concentration of molecules can be changed by chemical reactions and thereby offer a continuous readout. Yet computer architecture is cast in textbooks in terms of binary valued, Boolean variables. To enable reactive chemical systems to compute we show how, using the Cox interpretation of probability theory, one can transcribe the equations of c...

We describe a thermodynamics-motivated, information theoretic analysis of proteomic data collected from a series of 8 glioblastoma multiforme (GBM) tumors. GBMs are considered here as prototypes of heterogeneous cancers. That heterogeneity is viewed here as manifesting in different unbalanced biological processes that are associated with thermodyna...

A single electron dynamic memory is designed based on the non-equilibrium dynamics of charge states in electrostatically-defined metallic quantum dots. Using the orthodox theory for computing the transfer rates and a master equation, we model the dynamical response of devices consisting of a charge sensor coupled to either a single and or a double...

A single electron dynamic memory is designed based on the non-equilibrium dynamics of charge states in electrostatically-defined metallic quantum dots. Using the orthodox theory for computing the transfer rates and a master equation, we model the dynamical response of devices consisting of a charge sensor coupled to either a single and or a double...

An ultrafast electronic excitation of N2 in the vacuum ultraviolet creates a nonstationary coherent linear superposition of interacting valence and Rydberg states resulting in a net oscillating dipole moment. There is therefore a linear response to an electrical field that can be queried by varying the time delay between the pump and a second optic...

A kinetic, single-cell proteomic study of chemically induced carcinogenesis is interpreted by treating the single-cell data as fluctuations of an open system transitioning between different steady states. In analogy to a first-order transition, phase coexistence and the loss of degrees of freedom are observed. The transition is detected well before...

Experimental biology is providing the distribution of numerous different biological molecules inside cells and in body fluids of patients. Statistical methods of analysis have very successfully examined these rather large databases. We seek to use a thermodynamic analysis to provide a physical understanding and quantitative characterization of huma...

Non-Boolean computations implementing operations on multivalued variable, beyond base 2 allow enhanced computational complexity. We introduce DNA as a functional material for ternary computing, and particularly demonstrate the use of three-valued oligonucleotide inputs to construct a 3×3 multiplication table. The system consists of two three-valued...

Gliomablastoma multiform (GBM) is the most fatal form of all brain cancers in humans. Currently there are limited diagnostic tools for GBM detection. Here, we applied surprisal analysis, a theory grounded in thermodynamics, to unveil how biomolecule energetics, specifically a redistribution of free energy amongst microRNAs (miRNAs), results in a sy...

In nature, post-transcriptional alternative splicing processes expand the proteome biodiversity, providing means to synthesize various protein isoforms. We describe the input-guided assembly of a DNAzyme-based full-adder computing system, which mimics functions of the natural processes by increasing the diversity of logic elements by the reconfigur...

The control of electronic dynamics in the neutral electronic states of LiH before the onset of significant nuclei motion is investigated using a Negative-Neutral-Positive (Ne-Ne-Po) ultrafast IR pump - atto pulse train (APT) probe scheme. Starting from the GS of the anion, LiH-, multiphoton ultrafast electron detachment and subsequent excitation of...

The information about an observable A provided by an indirect experiment in which observable B is measured is used as a criterion for comparing the performance of different observables B and for selecting an optimal initial state.

The principles underlying the implementation of complex logic operations at the molecular scale are outlined. Different types of logic machines can be implemented. The simplest ones are combinational circuits, in which logic gates are connected in order to compute a logic function. We discuss several physical realizations of combinational circuits...

Selectivity of product formation in activated chemical reactions can be accomplished by the control of energy acquisition, storage and disposal in the molecular system. This goal can be achieved by ‘passive control’ via energy acquisition, i.e., selecting the initial conditions and letting the system evolve under its own Hamiltonian, and by the ‘ac...

The total wave function of an impure molecular crystal is resolved, using the partitioning technique, into two components, one restricted to the host lattice and one which describes the interaction between the isolated impurities and the host. The two components differ by a phase which can be a rapidly varying function of the energy. Typical interf...

Symmetry scattering in spaces of rank higher than one is discussed. For such spaces one can introduce independent "directions" and thereby endow the scattering region with internal structure. Two distinct types of applications are treated: the angular distribution for scattering into different space directions as a function of the energy and scatte...

The entropy of the response of a system to a probe is proposed as a quantitative measure for the fraction of the total phase space accessed by that probe. The measure has the required dynamic range and its value depends both on the Hamiltonian of the system and on the probe. Different probes can be considered. The role of quantal fluctuations is ex...

Background PreliminariesDynamicsConcluding Remarks

IntroductionHigh-Resolution Spectroscopy and Intramolecular DynamicsLaser Studies of Chemical ReactivityLevel Structure and Dynamics of Clusters

IntroductionThe Distribution of FluctuationsThe Distribution of SpectraSummary

Computing the entropy of a system from a single trajectory is discussed when the energy exchange with the environment includes both mechanical and thermal terms. The physical example chosen as an illustration is a cluster of atoms impacting a hard surface. Each atom of the cluster interacts with the smooth surface by a momentum transfer using the h...

There is no unique stationary scattering theory. We distinguish the main versions by analyzing the different idealizations (spatial or temporal boundary conditions - SBC and TBC, respectively) implied by different orders of taking the limits of infinite volume and of sharp initial conditions. The relations of the different representations are discu...

The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics s...

The temperature and solvent composition dependence of the electrochemically stimulated rate of shuttling of the redox-active cyclophane, cyclobis(paraquat-p-phenylene), on a molecular string has been studied. The molecular string includes a pi-donor diiminebenzene-site that is associated on one side with an electrode, and stoppered on the other sid...

The scope and prospects of physical chemistry in the beginning of 21st century are presented. Physical chemistry helps to understand the simple model systems on the molecular scale, the structure and dynamics of small molecules, monoatomic and diatomic species, and their surfaces. The study opened ways to explore more complex systems, proteins, mol...

The hypersonic impact of a molecular cluster at a hard surface generates a hot and compressed globule that in a very short while expands and shatters. Even at impact velocities below the onset of ionization this hot matter has a time varying transient dipole that can emit light. We discuss the spectral range and the power (in absolute units) of the...

Emission spectra of mixed rare gas clusters, heated by impact with a hard surface at hypersonic velocities, are shown to extend into the near-IR and visible regimes. The emission is due to the transient dipole that arises during the collision of dissimilar atoms. The simulations are for a cluster that remains in the electronic ground state througho...

This chapter provides a survey of properties and behavior of atomic and molecular clusters. Beginning with a review of the means available for studying clusters, the discussion goes on to the kinds of bonding they exhibit and the kinds of structures that result. The next section discusses the thermodynamics of clusters, especially their phase behav...

Measuring the wavelength dependence of photodissociation transition amplitudes to crossing electronic states is discussed with reference to extracting time domain information. Outwards from the crossing the system evolves on one or the other state as ascertained from the electronic state of the products. One can therefore measure the phase differen...

An experimental study of molecular fusion in fullerene–fullerene collisions is presented and the theoretical interpretation of the cross section is reconsidered in terms of phase space arguments and competition with direct collision induced dissociation. The form and absolute magnitude of the cross sections for C+60+C70 (or C+70+C60) and C+70+C70 c...

We present the real-space block renormalization group equations for fermion systems described by a Hubbard Hamiltonian on a triangular lattice with hexagonal blocks. The conditions that keep the equations from proliferation of the couplings are derived. Computational results are presented including the occurrence of a first-order metal-insulator tr...

A conformal symmetry for the heat or time dependent Schrodinger equation (@ t Gamma H )Psi = 0 is a linear differential operator L such that LPsi is a solution of the equation for every solution Psi. In essence L is a time-dependent constant of the motion. For equations in one spatial dimension it is possible to compute, at least formally, all conf...

The dynamics of the K+CH3I reaction is discussed with special reference to two factors that govern the electron transfer. One is that at higher collision velocity the behavior need not be adiabatic so that there can be a finite probability for the electron not to transfer, resulting in no reaction. The other is the marked increase of the electron a...

Computational results for the surface impact of (CH3I)n clusters are presented, and the dynamics of formation of molecular products is examined. The mechanism is compared to the high energy bimolecular CH3I + CH3I collision and to other reactions in impact-heated clusters, in particular, the burning of air. The results are discussed in reference to...

Why do some quite complex events appear to be built up from seemingly independent elementary events? It is, of course, fortunate that this is so, for otherwise, it would be hard to analyze the world around us. But the technical question remains. It is here argued that a sufficient condition is that the possible complex events all have the same sum(...

The effective energy threshold for the crossing into an electronically excited state and the post threshold rise of the yield of crossing are discussed. The time-dependent Schrödinger equation for multiple electronic states is solved using the full multiple spawning (FMS) methodology. The quantal results are compared with classical path methods. Th...

The full multiple spawning (FMS) methodology for solving the time dependent Schrödinger equation for multiple electronic states is extended to reactive collisions on several electronic states. The computational complexity remains unchanged, less than double that of a quasiclassical trajectory computation. It is shown how the spawning approach can d...

An inversion procedure which provides the most conservative inference for an unknown function in terms of partial data is discussed on the basis of information theoretic considerations. The method is based on the procedure of maximal entropy, but is not limited to the estimation of unknown probabilities. Rather, inductive inferences can be drawn re...

Translational to electronic energy transfer with or without a concomitant chemical reaction is studied for the Evans–Polanyi model. We explore the possibility of light emission from an electronically excited state following a high-energy collision. This can be viewed as an inverse process to a Woodward–Hoffmann photochemically allowed four-center r...

The probability of an error in a Monte Carlo integration is shown to be exponentially small in the number of points used, with the magnitude of the exponent being determined by a relevant entropy. Implications for importance sampling and for the significance of the maximum entropy formalism are discussed. Specifically it is shown that the optimal s...

The hypothetical four-center nitrogen exchange reaction of N-2 + N-2 is analyzed. We show that the three level crossings accompanying the least-motion nitrogen exchange reaction occur at different points along the reaction coordinate, leading to a mechanism requiring three ''singly forbidden'' reaction steps. Simple MO arguments show that the loss...

Chemical reaction dynamics is making increasing contact with 'real' chemistry: examination of more elaborate reaction mechanisms typical of organic chemistry, the study of chemical reactions where the medium plays an active role (as is often the case in solution and on surfaces) and the ability to mimic systems of biochemical complexity are all of...

High molecular Rydberg states, whose time evolution exhibits multiple time scales are discussed as an example of a system which can be examined in detail. Three bottlenecks to the sampling of phase space, associated with an incomplete mixing of the zeroth order quantum numbers, are identified. The physics of all three is that the number of open ion...

The onset of a shattering regime when a supersonic cluster undergoes an ultrafast heating by its impact at a surface, proposed on the basis of an information theoretic analysis, has now been demonstrated experimentally for molecular clusters. It is emphasized that the sudden onset of shattering as a function of impact velocity is a robust result de...

An algebraic formulation of quantum mechanics is presented. In this formulation, operators of interest are expanded onto elements of an algebra, G. For bound state problems in nu dimensions the algebra G is taken to be U(nu + 1). Applications to the structure of molecules are presented.

We address some of the unique and basic features of molecular clusters, which involve (i) surface, interior, and site-selective energetics and dynamics, and (ii) the size dependence of the energetic, spectroscopic, electromagnetic, and dynamic attributes of large finite systems. Cluster-size equations provide a unified (but not universal) descripti...

A new area in dynamics, characterized by collision times shorter than hitherto studied, is discussed with special reference to four-center reactions. Under the unusual combination of conditions made possible within an impact heated cluster, the nominally four-center reactions can be made to proceed (on the computer) via the four-center mechanism as...

A computationally tractable approximation for both interstate and intrastate dynamics is derived and applied. The correlation between the electronic and nuclear degrees of freedom is explicitly allowed for in that there is an equation of motion for the nuclear dynamics on each electronic state. These equations for the intrastate dynamics are couple...

The shattering transition expected upon ultrafast heating has been observed in size selected \(NH3\)n-1NH+4 clusters, n = 4 to 40, upon impact at supersonic velocities on a graphite surface. As a function of the impact velocity, the transition is between the recoil of the intact parent cluster and the appearance of small, n = 1,2,... charged fragme...

Cluster impact activation of high-energy chemical reactions is suggested by our simulations to provide an effective process. For four-center rearrangements it is shown that the reaction can proceed by both a concerted and a two-step mechanism. The relative importance of the two mechanisms is shown to be a stereodynamic effect, governed by the natur...