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

Physical Review A

Theory of retrieving orientation-resolved molecular information using time-domain rotational coherence spectroscopy

Xu Wang, Anh-Thu Le, Zhaoyan Zhou, Hui Li Wei, C. D. Lin

Published Aug 28, 2017• 19 citations
Publisher

Abstract

We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija et al., arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method.

DOI
10.1103/physreva.96.023424

Related papers

State reconstruction of molecular spatial rotation

Xiao Qin, Junyi Gao

We establish a reconstruction approach for the rotational quantum state of linear molecules possessing a magnetic manifold. Our approximate method contains an iteration with generalized matrix inverses, processing the tomographic integral of the time-dependent molecular-axis distribution in a polar angle. As shown in a simulated example for an alignment state, the density matrix is determined in a high fidelity. An analytic tomographic formula is also derived for the symmetric top rotation. The state coherent in the quantum space of both the angular momentum and its magnetic projection can be approximately retrieved from the observable time-resolved solid-angle distribution of the molecular axis.

Chinese Physics B•Feb 1, 2012•1 citation

State reconstruction of molecular spatial rotation

覃晓, 高军毅

We establish a reconstruction approach for the rotational quantum state of linear molecules possessing a magnetic manifold.Our approximate method contains an iteration with generalized matrix inverses,processing the tomographic integral of the time-dependent molecular-axis distribution in a polar angle.As shown in a simulated example for an alignment state,the density matrix is determined in a high fidelity.An analytic tomographic formula is also derived for the symmetric top rotation.The state coherent in the quantum space of both the angular momentum and its magnetic projection can be approximately retrieved from the observable time-resolved solid-angle distribution of the molecular axis.

Chinese Physics B•Jan 1, 2012•0 citations

Theory of dipole moment reconstruction by attosecond transient absorption spectroscopy

Xiaoxia Wu, Linxuan Zhang, Shaofeng Zhang +1 more

We propose a general procedure for the reconstruction of time-dependent dipole moment via transient absorption spectrum, within the framework of linear response theory. The reconstruction method is demonstrated with two examples: the self-reconstruction of extreme-ultraviolet-light-atom interaction (analytically) and the infrared-dressed helium system (numerically). A correlation coefficient is introduced to quantify the fidelity of the reconstruction, which reaches almost 100$%$ over a wide range of laser parameters and thus indicates the robustness of our reconstruction method. Our theory provides a solid basis for understanding the recent experiment [Phys. Rev. Lett. 121, 173005 (2018)], explaining when and why the dipole moment can be well reconstructed solely from the absorption spectrum even without exact knowledge of the attosecond probe pulse.

Physical Review A•Dec 29, 2021•7 citations

Entanglement of molecular-orientation, rotational and orbital degrees of freedom in multiphoton orientational wave packets

Constantin Maïnos, G. Dutier, Jules Grucker +3 more

Multiphoton orientational wave packets induced by short resonant polarized laser pulses in a rotationally-frozen interacting molecule contain relevant information. The entanglement of the orbital, rotational and orientational degrees of freedom shows a strong dependence on the polarization state of the absorbed photons and the space orientation of the interacting molecule and enables one to assign the orbital state of the excited molecular electron, to measure the space orientation of the interacting molecule from the orientational recurrences, to relate the measured temporal widths to the angular momentum photon state and the coherence of the laser pulse, to obtain information on the ground rotational state, or to measure the effective temperature of an isotropic molecular assembly. The space orientation of a small number of independent molecules can be distinguished from their distinct orientational dependence in the formation of the individual orientational wave packets.

Journal of Physics B Atomic Molecular and Optical Physics•Jan 24, 2008•1 citation

Precise quantum control of unidirectional field-free molecular orientation

Qian-Qian Hong, Zhe-Jun Zhang, Chuan-Cun Shu +3 more

The capability to control molecular rotation for field-free orientation, which arranges molecules in specific spatial directions without external fields, is crucial in physics, chemistry, and quantum information science. However, conventional methods typically lead to transient orientations characterized by periodic directional reversals and necessitate the generation of coherent superpositions across a broad spectrum of rotational states of ultracold molecules. In this work, we develop a theoretical framework for achieving unidirectional field-free orientation by selectively manipulating two specific rotational states of symmetric top molecules. By leveraging the interplay between coherent superpositions and the precise selection of initial states, we demonstrate that both the maximum achievable orientation and its direction can be effectively controlled. To attain the desired two-state orientation, we present a quantum control strategy that utilizes a single control pulse, significantly simplifying the complexities of conventional multistate or multipulse schemes. Numerical simulations validate the effectiveness and feasibility of this approach for methyl iodide (CH$_3$I) molecules, even when accounting for molecular centrifugal distortion.The results highlight the critical roles of initial-state selection and quantum coherence in achieving long-lasting, high unidirectional molecular orientation, opening new directions in stereochemistry, precision spectroscopy, and quantum computing.

quant-pharXiv:2512.21012•Dec 25, 2025•0 citations

Effect of rotational-state-dependent molecular alignment on the optical dipole force

Lee Yeong Kim, Ju Hyeon Lee, Hye Ah Kim +3 more

The properties of molecule-optical elements such as lenses or prisms based on the interaction of molecules with optical fields depend in a crucial way on the molecular quantum state and its alignment created by the optical field. Herein, we consider the effects of state-dependent alignment in estimating the optical dipole force acting on the molecules and, to this end, introduce an effective polarizability which takes proper account of molecular alignment and is directly related to the alignment-dependent optical dipole force. We illustrate the significance of including molecular alignment in the optical dipole force by a trajectory study that compares previously used approximations with the present approach. The trajectory simulations were carried out for an ensemble of linear molecules subject to either propagating or standing-wave optical fields for a range of temperatures and laser intensities. The results demonstrate that the alignment-dependent effective polarizability can serve to provide correct estimates of the optical dipole force, on which a state-selection method applicable to nonpolar molecules could be based. We note that an analogous analysis of the forces acting on polar molecules subject to an inhomogeneous static electric field reveals a similarly strong dependence on molecular orientation.

arXiv:1606.00516•Physical Review A•Jul 27, 2016•6 citations
We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija et al., arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method.
We establish a reconstruction approach for the rotational quantum state of linear molecules possessing a magnetic manifold. Our approximate method contains an iteration with generalized matrix inverses, processing the tomographic integral of the time-dependent molecular-axis distribution in a polar angle. As shown in a simulated example for an alignment state, the density matrix is determined in a high fidelity. An analytic tomographic formula is also derived for the symmetric top rotation. The state coherent in the quantum space of both the angular momentum and its magnetic projection can be approximately retrieved from the observable time-resolved solid-angle distribution of the molecular axis.
We establish a reconstruction approach for the rotational quantum state of linear molecules possessing a magnetic manifold.Our approximate method contains an iteration with generalized matrix inverses,processing the tomographic integral of the time-dependent molecular-axis distribution in a polar angle.As shown in a simulated example for an alignment state,the density matrix is determined in a high fidelity.An analytic tomographic formula is also derived for the symmetric top rotation.The state coherent in the quantum space of both the angular momentum and its magnetic projection can be approximately retrieved from the observable time-resolved solid-angle distribution of the molecular axis.
We propose a general procedure for the reconstruction of time-dependent dipole moment via transient absorption spectrum, within the framework of linear response theory. The reconstruction method is demonstrated with two examples: the self-reconstruction of extreme-ultraviolet-light-atom interaction (analytically) and the infrared-dressed helium system (numerically). A correlation coefficient is introduced to quantify the fidelity of the reconstruction, which reaches almost 100% over a wide range of laser parameters and thus indicates the robustness of our reconstruction method. Our theory provides a solid basis for understanding the recent experiment [Phys. Rev. Lett. 121, 173005 (2018)], explaining when and why the dipole moment can be well reconstructed solely from the absorption spectrum even without exact knowledge of the attosecond probe pulse.
Multiphoton orientational wave packets induced by short resonant polarized laser pulses in a rotationally-frozen interacting molecule contain relevant information. The entanglement of the orbital, rotational and orientational degrees of freedom shows a strong dependence on the polarization state of the absorbed photons and the space orientation of the interacting molecule and enables one to assign the orbital state of the excited molecular electron, to measure the space orientation of the interacting molecule from the orientational recurrences, to relate the measured temporal widths to the angular momentum photon state and the coherence of the laser pulse, to obtain information on the ground rotational state, or to measure the effective temperature of an isotropic molecular assembly. The space orientation of a small number of independent molecules can be distinguished from their distinct orientational dependence in the formation of the individual orientational wave packets.
The capability to control molecular rotation for field-free orientation, which arranges molecules in specific spatial directions without external fields, is crucial in physics, chemistry, and quantum information science. However, conventional methods typically lead to transient orientations characterized by periodic directional reversals and necessitate the generation of coherent superpositions across a broad spectrum of rotational states of ultracold molecules. In this work, we develop a theoretical framework for achieving unidirectional field-free orientation by selectively manipulating two specific rotational states of symmetric top molecules. By leveraging the interplay between coherent superpositions and the precise selection of initial states, we demonstrate that both the maximum achievable orientation and its direction can be effectively controlled. To attain the desired two-state orientation, we present a quantum control strategy that utilizes a single control pulse, significantly simplifying the complexities of conventional multistate or multipulse schemes. Numerical simulations validate the effectiveness and feasibility of this approach for methyl iodide (CH3_33​I) molecules, even when accounting for molecular centrifugal distortion.The results highlight the critical roles of initial-state selection and quantum coherence in achieving long-lasting, high unidirectional molecular orientation, opening new directions in stereochemistry, precision spectroscopy, and quantum computing.
The properties of molecule-optical elements such as lenses or prisms based on the interaction of molecules with optical fields depend in a crucial way on the molecular quantum state and its alignment created by the optical field. Herein, we consider the effects of state-dependent alignment in estimating the optical dipole force acting on the molecules and, to this end, introduce an effective polarizability which takes proper account of molecular alignment and is directly related to the alignment-dependent optical dipole force. We illustrate the significance of including molecular alignment in the optical dipole force by a trajectory study that compares previously used approximations with the present approach. The trajectory simulations were carried out for an ensemble of linear molecules subject to either propagating or standing-wave optical fields for a range of temperatures and laser intensities. The results demonstrate that the alignment-dependent effective polarizability can serve to provide correct estimates of the optical dipole force, on which a state-selection method applicable to nonpolar molecules could be based. We note that an analogous analysis of the forces acting on polar molecules subject to an inhomogeneous static electric field reveals a similarly strong dependence on molecular orientation.