Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

The Journal of Physical Chemistry A

Mechanistic Analysis of Optimal Dynamic Discrimination of Similar Quantum Systems

Abhra Mitra, HERSCHEL A. RABITZ

Published May 1, 2004• 22 citations
Publisher

Abstract

Optimal dynamic discrimination (ODD) was recently introduced as a technique for maximally drawing out and detecting the differences between similar quantum systems by exploiting their controllable dynamical properties. As a simulation of ODD, optimal fields were found that successfully discriminated among similar species, but the underlying mechanisms of the process remained obscure. Hamiltonian encoding (HE) has been introduced as a technique for identifying the mechanisms of controlled quantum dynamics. The results of a HE based simulation analysis of ODD are presented in this paper. Different types and degrees of constructive and destructive interference are shown to underly the controlled discrimination processes. In general, it is found that successful discrimination relies on more complex interfering pathways for increasingly similar systems or increasing numbers of similar quantum systems.

DOI
10.1021/jp0495390

Related papers

Optimal Dynamic Discrimination of Similar Molecules through Quantum Learning Control

Baiqing Li, Gabriel Turinici, Viswanath Ramakrishna +1 more

A paradigm for discriminating similar quantum systems in the laboratory is presented based on optimal control principles with the aid of closed loop learning algorithms. The optimal dynamic discrimination (ODD) process is simulated for a noninteracting mixture of up to three similar finite-dimensional quantum systems. The optimal control field giving rise to species discrimination, that considers the presence of field and observation noise, is deduced with a genetic algorithm (GA). The similar quantum systems yield distinct dynamics and detection signals, although influenced by the same control laser pulse. The ODD process is shown to operate by drawing on constructive and destructive interference effects to simultaneously maximize or minimize the signals from each of the species in the mixture. The ODD technique may have applications to the analysis and separation of possibly even complex chemical species.

The Journal of Physical Chemistry B•Jul 3, 2002•76 citations

Optimal Use of Laser Resources for Molecular Detection

HERSCHEL A. RABITZ

Similar molecules or materials have comparable composition, structure, and other properties thus making them difficult to discriminate for purposes of detection. Although the species may be spectrally similar, they each could have significantly different (quantum) dynamical behavior for detection. Optimal dynamic discrimination (ODD) aims to maximally draw out the differences among similar species by manipulating their molecular dynamics with optimized radiation resources. The highest degrees of discrimination arise upon exploiting control of the quantum dynamics of the species. Theoretical analysis shows that quantum systems differing even infinitesimally in character may be distinguished by means of their dynamics when acted upon by a suitably shaped control field. Simulations have demonstrated the capabilities of optimal discrimination in the presence of laser-pulse noise, signal detection errors, and imperfect signal detection resolution. Recent experiments have demonstrated the feasibility of ODD.

•Jan 1, 2013•0 citations

Exploring the capabilities of quantum optimal dynamic discrimination

Vincent Beltrani, Pritha Ghosh, HERSCHEL A. RABITZ

Optimal dynamic discrimination (ODD) uses closed-loop learning control techniques to discriminate between similar quantum systems. ODD achieves discrimination by employing a shaped control (laser) pulse to simultaneously exploit the unique quantum dynamics particular to each system, even when they are quite similar. In this work, ODD is viewed in the context of multiobjective optimization, where the competing objectives are the degree of similarity of the quantum systems and the level of controlled discrimination that can be achieved. To facilitate this study, the D-MORPH gradient algorithm is extended to handle multiple quantum systems and multiple objectives. This work explores the trade-off between laser resources (e.g., the length of the pulse, fluence, etc.) and ODD's ability to discriminate between similar systems. A mechanism analysis is performed to identify the dominant pathways utilized to achieve discrimination between similar systems.

The Journal of Chemical Physics•Apr 27, 2009•17 citations

Identifying mechanisms in the control of quantum dynamics through Hamiltonian encoding

Abhra Mitra, HERSCHEL A. RABITZ

A variety of means are now available to design control fields for manipulating the evolution of quantum systems. However, the underlying physical mechanisms often remain obscure, especially in the cases of strong fields and high quantum state congestion. This paper proposes a method to quantitatively determine the various pathways taken by a quantum system in going from the initial state to the final target. The mechanism is revealed by encoding a signal in the system Hamiltonian and decoding the resultant nonlinear distortion of the signal in the system time-evolution operator. The relevant interfering pathways determined by this analysis give insight into the physical mechanisms operative during the evolution of the quantum system. A hierarchy of mechanism identification algorithms with increasing ability to extract more detailed pathway information is presented. The mechanism identification concept is presented in the context of analyzing computer simulations of controlled dynamics. As illustrations of the concept, mechanisms are identified in the control of several simple, discrete-state quantum systems. The mechanism analysis tools reveal the roles of multiple interacting quantum pathways to maximally take advantage of constructive and destructive interference. Similar procedures may be applied directly in the laboratory to identify control mechanisms without resort to computer modeling, although this extension is not addressed in this paper.

Physical Review A•Mar 26, 2003•74 citations

Quantum control mechanism analysis through field based Hamiltonian encoding

Abhra Mitra, HERSCHEL A. RABITZ

Optimal control of quantum dynamics in the laboratory is proving to be increasingly successful. The control fields can be complex, and the mechanisms by which they operate have often remained obscure. Hamiltonian encoding (HE) has been proposed as a method for understanding mechanisms in quantum dynamics. In this context mechanism is defined in terms of the dominant quantum pathways leading to the final state of the controlled system. HE operates by encoding a special modulation into the Hamiltonian and decoding its signature in the dynamics to determine the dominant pathway amplitudes. Earlier work encoded the modulation directly into the Hamiltonian operators. This present work introduces the alternative scheme of field based HE, where the modulation is encoded into the control field and not directly into the Hamiltonian operators. This distinct form of modulation yields a new perspective on mechanism and is computationally faster than the earlier approach. Field based encoding is also an important step towards a laboratory based algorithm for HE as it is the only form of encoding that may be experimentally executed. HE is also extended to cover systems with noise and uncertainty and finally, a hierarchical algorithm is introduced to reveal mechanism in a stepwise fashion of ever increasing detail as desired. This new hierarchical algorithm is an improvement over earlier approaches to HE where the entire mechanism was determined in one stroke. The improvement comes from the use of less complex modulation schemes, which leads to fewer evaluations of Schrodinger's equation. A number of simulations are presented on simple systems to illustrate the new field based encoding technique for mechanism assessment.

The Journal of Chemical Physics•Nov 16, 2006•18 citations

Optimal dynamic discrimination of similar quantum systems with time series data

Baiqing Li, HERSCHEL A. RABITZ, Jean‐Pierre Wolf

Optimal dynamic discrimination (ODD) was proposed [Li et al., J. Phys. Chem. B 106, 8125 (2002)] as a paradigm for discriminating noninteracting similar quantum systems in a mixture. This paper extends the ODD concept to optimize a laser control pulse for guiding similar quantum systems such that each exhibits a distinct time series signal for maximum discrimination. The use of temporal data addresses various experimental difficulties, including noise in the laser pulse, signal detection errors, and finite time resolution in the signal. Simulations of ODD with time series data are presented to explore these effects. It is found that the use of an optimally chosen control pulse can significantly enhance the discrimination quality. The ODD technique is also adapted to the case where the sample contains an unknown background species.

The Journal of Chemical Physics•Apr 15, 2005•38 citations
Optimal dynamic discrimination (ODD) was recently introduced as a technique for maximally drawing out and detecting the differences between similar quantum systems by exploiting their controllable dynamical properties. As a simulation of ODD, optimal fields were found that successfully discriminated among similar species, but the underlying mechanisms of the process remained obscure. Hamiltonian encoding (HE) has been introduced as a technique for identifying the mechanisms of controlled quantum dynamics. The results of a HE based simulation analysis of ODD are presented in this paper. Different types and degrees of constructive and destructive interference are shown to underly the controlled discrimination processes. In general, it is found that successful discrimination relies on more complex interfering pathways for increasingly similar systems or increasing numbers of similar quantum systems.
A paradigm for discriminating similar quantum systems in the laboratory is presented based on optimal control principles with the aid of closed loop learning algorithms. The optimal dynamic discrimination (ODD) process is simulated for a noninteracting mixture of up to three similar finite-dimensional quantum systems. The optimal control field giving rise to species discrimination, that considers the presence of field and observation noise, is deduced with a genetic algorithm (GA). The similar quantum systems yield distinct dynamics and detection signals, although influenced by the same control laser pulse. The ODD process is shown to operate by drawing on constructive and destructive interference effects to simultaneously maximize or minimize the signals from each of the species in the mixture. The ODD technique may have applications to the analysis and separation of possibly even complex chemical species.
Similar molecules or materials have comparable composition, structure, and other properties thus making them difficult to discriminate for purposes of detection. Although the species may be spectrally similar, they each could have significantly different (quantum) dynamical behavior for detection. Optimal dynamic discrimination (ODD) aims to maximally draw out the differences among similar species by manipulating their molecular dynamics with optimized radiation resources. The highest degrees of discrimination arise upon exploiting control of the quantum dynamics of the species. Theoretical analysis shows that quantum systems differing even infinitesimally in character may be distinguished by means of their dynamics when acted upon by a suitably shaped control field. Simulations have demonstrated the capabilities of optimal discrimination in the presence of laser-pulse noise, signal detection errors, and imperfect signal detection resolution. Recent experiments have demonstrated the feasibility of ODD.
Optimal dynamic discrimination (ODD) uses closed-loop learning control techniques to discriminate between similar quantum systems. ODD achieves discrimination by employing a shaped control (laser) pulse to simultaneously exploit the unique quantum dynamics particular to each system, even when they are quite similar. In this work, ODD is viewed in the context of multiobjective optimization, where the competing objectives are the degree of similarity of the quantum systems and the level of controlled discrimination that can be achieved. To facilitate this study, the D-MORPH gradient algorithm is extended to handle multiple quantum systems and multiple objectives. This work explores the trade-off between laser resources (e.g., the length of the pulse, fluence, etc.) and ODD's ability to discriminate between similar systems. A mechanism analysis is performed to identify the dominant pathways utilized to achieve discrimination between similar systems.
A variety of means are now available to design control fields for manipulating the evolution of quantum systems. However, the underlying physical mechanisms often remain obscure, especially in the cases of strong fields and high quantum state congestion. This paper proposes a method to quantitatively determine the various pathways taken by a quantum system in going from the initial state to the final target. The mechanism is revealed by encoding a signal in the system Hamiltonian and decoding the resultant nonlinear distortion of the signal in the system time-evolution operator. The relevant interfering pathways determined by this analysis give insight into the physical mechanisms operative during the evolution of the quantum system. A hierarchy of mechanism identification algorithms with increasing ability to extract more detailed pathway information is presented. The mechanism identification concept is presented in the context of analyzing computer simulations of controlled dynamics. As illustrations of the concept, mechanisms are identified in the control of several simple, discrete-state quantum systems. The mechanism analysis tools reveal the roles of multiple interacting quantum pathways to maximally take advantage of constructive and destructive interference. Similar procedures may be applied directly in the laboratory to identify control mechanisms without resort to computer modeling, although this extension is not addressed in this paper.
Optimal control of quantum dynamics in the laboratory is proving to be increasingly successful. The control fields can be complex, and the mechanisms by which they operate have often remained obscure. Hamiltonian encoding (HE) has been proposed as a method for understanding mechanisms in quantum dynamics. In this context mechanism is defined in terms of the dominant quantum pathways leading to the final state of the controlled system. HE operates by encoding a special modulation into the Hamiltonian and decoding its signature in the dynamics to determine the dominant pathway amplitudes. Earlier work encoded the modulation directly into the Hamiltonian operators. This present work introduces the alternative scheme of field based HE, where the modulation is encoded into the control field and not directly into the Hamiltonian operators. This distinct form of modulation yields a new perspective on mechanism and is computationally faster than the earlier approach. Field based encoding is also an important step towards a laboratory based algorithm for HE as it is the only form of encoding that may be experimentally executed. HE is also extended to cover systems with noise and uncertainty and finally, a hierarchical algorithm is introduced to reveal mechanism in a stepwise fashion of ever increasing detail as desired. This new hierarchical algorithm is an improvement over earlier approaches to HE where the entire mechanism was determined in one stroke. The improvement comes from the use of less complex modulation schemes, which leads to fewer evaluations of Schrodinger's equation. A number of simulations are presented on simple systems to illustrate the new field based encoding technique for mechanism assessment.
Optimal dynamic discrimination (ODD) was proposed [Li et al., J. Phys. Chem. B 106, 8125 (2002)] as a paradigm for discriminating noninteracting similar quantum systems in a mixture. This paper extends the ODD concept to optimize a laser control pulse for guiding similar quantum systems such that each exhibits a distinct time series signal for maximum discrimination. The use of temporal data addresses various experimental difficulties, including noise in the laser pulse, signal detection errors, and finite time resolution in the signal. Simulations of ODD with time series data are presented to explore these effects. It is found that the use of an optimally chosen control pulse can significantly enhance the discrimination quality. The ODD technique is also adapted to the case where the sample contains an unknown background species.