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

arXiv:1111.5112 · International Journal of Quantum Information

COHERENT CONTROL OF MESOSCOPIC SUPERPOSITIONS IN A DIATOMIC MOLECULE

Suranjana Ghosh

Published Mar 1, 2012• 11 citations
arXivHTMLPDF

Abstract

A phase controlled wave packet, recently used in experiment of wave packet interferometry of a diatomic molecule, is investigated to obtain mesoscopic superposition structures, useful in quantum metrology. This analysis provides a new way of obtaining sub-Planck scale structures at smaller time scale of revival dynamics. We study a number of situations for delineating the smallest interference structures and their control by tailoring the relative phase between two subsidiary wave packets. We also find the most appropriate state, so far, for high precision parameter estimation in a system of diatomic molecule.

DOI
10.1142/s0219749912500141

Related papers

Mesoscopic superposition and sub-Planck-scale structure in molecular wave packets

Suranjana Ghosh, Aravind Chiruvelli, J. Banerji +1 more

We demonstrate the possibility of realizing sub-Planck-scale structures in the mesoscopic superposition of molecular wave packets involving vibrational levels. The time evolution of the wave packet, taken here as the SU(2) coherent state of the Morse potential describing hydrogen iodide molecules, produces macroscopic-quantum-superposition-like states, responsible for the above phenomenon. We investigate the phase-space dynamics of the coherent state through the Wigner function approach and identify the interference phenomena behind the sub-Planck-scale structures. The optimal parameter ranges are specified for observing these features.

arXiv:quant-ph/0507082•Physical Review A•Jan 30, 2006•38 citations

Controlling Wave Packet Interference with Attosecond Precision

Hiroyuki Katsuki, Kenji Ohmori

The interference is an intrinsic feature of waves. In the quantum world, a variety of interferometric measurements of matter waves have so far been performed to demonstrate the wave-particle duality. In this short note, we review such quantum interferometric measurements of wave packets (WP's) in atoms and molecules such as Rydberg WP's in atoms and vibrational WP's in molecules. We also show the results of our recent WP interferometry with the iodine molecules, which have been performed by phase-locking a pair of femtosecond laser pulses on the attosecond time scale.

The Review of Laser Engineering•Jan 1, 2008•0 citations

Enhanced quantum sensitivity in a vibrating diatomic molecule due to a rotational amendment

Suranjana Ghosh, Utpal Roy

Quantum sensitivity is an important issue in the field of quantum metrology where sub-Planck scale structures play a crucial role in the Heisenberg limited measurement. We investigate the mesoscopic superposition structures, particularly for well-known catlike and compasslike states, in the rotating Morse system where sub-Planck scale structures originate in the dynamics of a suitably constructed SU(2) coherent state. A detail study of the sensitivity analysis reveals that rotational coupling in the vibrational wave packet can be used as a probe to enhance the sensitivity limit in a diatomic molecule. The maximum sensitivity limit is identified with the rotational amendment, and a quantitative measure of the angle of rotation for different rotational levels is also given. The correspondence of the numerical result with the angle of rotation is also delineated in phase-space Wigner representation.

arXiv:1504.00370•Physical Review A•Aug 18, 2014•10 citations

Mesoscopic superposition of states with sub-Planck structures in phase space

G. S. Agarwal, Pradyumna K. Pathak

We propose the cavity quantum electrodynamics method, using dispersive interaction between atoms and a high-quality cavity to realize the mesoscopic superposition of coherent states that would exhibit sub-Planck structures in phase space, i.e., the structures at a scale smaller than the Plank's constant $(\ensuremath{\hbar})$. These structures are direct signatures of quantum coherence and are formed as a result of interference between the two superposed cat states. In particular we focus on a superposition involving four coherent states. We show interferences in the conditional measurements involving two atoms.

arXiv:quant-ph/0312092•Physical Review A•Nov 11, 2004•57 citations

Sub-Planck-scale structures in a vibrating molecule in the presence of decoherence

Suranjana Ghosh, Utpal Roy, Claudiu Genes +1 more

We study the effect of decoherence on the sub-Planck scale structures of the vibrational wave packet of a molecule. The time evolution of these wave packets is investigated under the influence of a photonic or phononic environment. We determine the master equation describing the reduced dynamics of the wave packet and analyze the sensitivity of the sub-Planck structures against decoherence in the case of a hydrogen iodide (HI) molecule.

arXiv:0902.4474•Physical Review A•May 5, 2009•35 citations

Toward Coherent Control Around the Quantum-Classical Boundary

Hiroyuki Katsuki, Kenji Ohmori

Coherent control is a technique to manipulate the amplitudes and phases of wave functions by exploiting the coherent property of light. It is of great importance for the development of quantum technologies including quantum information processing and chemical reaction control as well as for addressing fundamental problems in quantum mechanics such as the quantum–classical boundary. In this chapter, we describe the development and applications of coherent control based on wave-packet interferometry with attosecond precision, which has been made possible by tuning the delay between two laser pulses on the attosecond time scale. This technique has been applied to several different hierarchies from simple to complex quantum systems: (i) isolated iodine molecules in the gas phase, (ii) molecular crystals of para-hydrogen, and (iii) single crystals of bismuth. In system (i), we have controlled and visualized the interference of vibrational wave packets in the isolated iodine molecules, and that wave-packet interference has been utilized to develop a molecular computer, which executes ultrafast Fourier transform. In system (ii), we have manipulated vibrational wave-functions delocalized in a para-hydrogen crystal. The long coherence lifetime of para-hydrogen crystals is a promising resource to preserve quantum information in bulk solids. In system (iii), we have controlled the excitation ratio of two orthogonal coherent phonon modes, whose coherent superposition has allowed for active control of ultrafast two-dimensional atomic motions in a single crystal of bismuth. Those atomic motions have been visualized by density functional theory calculations. Finally, the coherent control of an ensemble of ultracold Rydberg atoms is briefly discussed as future perspectives for exploring the quantum–classical boundary.

Advances in chemical physics•Apr 1, 2016•0 citations
A phase controlled wave packet, recently used in experiment of wave packet interferometry of a diatomic molecule, is investigated to obtain mesoscopic superposition structures, useful in quantum metrology. This analysis provides a new way of obtaining sub-Planck scale structures at smaller time scale of revival dynamics. We study a number of situations for delineating the smallest interference structures and their control by tailoring the relative phase between two subsidiary wave packets. We also find the most appropriate state, so far, for high precision parameter estimation in a system of diatomic molecule.
We demonstrate the possibility of realizing sub-Planck-scale structures in the mesoscopic superposition of molecular wave packets involving vibrational levels. The time evolution of the wave packet, taken here as the SU(2) coherent state of the Morse potential describing hydrogen iodide molecules, produces macroscopic-quantum-superposition-like states, responsible for the above phenomenon. We investigate the phase-space dynamics of the coherent state through the Wigner function approach and identify the interference phenomena behind the sub-Planck-scale structures. The optimal parameter ranges are specified for observing these features.
The interference is an intrinsic feature of waves. In the quantum world, a variety of interferometric measurements of matter waves have so far been performed to demonstrate the wave-particle duality. In this short note, we review such quantum interferometric measurements of wave packets (WP's) in atoms and molecules such as Rydberg WP's in atoms and vibrational WP's in molecules. We also show the results of our recent WP interferometry with the iodine molecules, which have been performed by phase-locking a pair of femtosecond laser pulses on the attosecond time scale.
Quantum sensitivity is an important issue in the field of quantum metrology where sub-Planck scale structures play a crucial role in the Heisenberg limited measurement. We investigate the mesoscopic superposition structures, particularly for well-known catlike and compasslike states, in the rotating Morse system where sub-Planck scale structures originate in the dynamics of a suitably constructed SU(2) coherent state. A detail study of the sensitivity analysis reveals that rotational coupling in the vibrational wave packet can be used as a probe to enhance the sensitivity limit in a diatomic molecule. The maximum sensitivity limit is identified with the rotational amendment, and a quantitative measure of the angle of rotation for different rotational levels is also given. The correspondence of the numerical result with the angle of rotation is also delineated in phase-space Wigner representation.
We propose the cavity quantum electrodynamics method, using dispersive interaction between atoms and a high-quality cavity to realize the mesoscopic superposition of coherent states that would exhibit sub-Planck structures in phase space, i.e., the structures at a scale smaller than the Plank's constant $(\ensuremath{\hbar})$. These structures are direct signatures of quantum coherence and are formed as a result of interference between the two superposed cat states. In particular we focus on a superposition involving four coherent states. We show interferences in the conditional measurements involving two atoms.
Coherent control is a technique to manipulate the amplitudes and phases of wave functions by exploiting the coherent property of light. It is of great importance for the development of quantum technologies including quantum information processing and chemical reaction control as well as for addressing fundamental problems in quantum mechanics such as the quantum–classical boundary. In this chapter, we describe the development and applications of coherent control based on wave-packet interferometry with attosecond precision, which has been made possible by tuning the delay between two laser pulses on the attosecond time scale. This technique has been applied to several different hierarchies from simple to complex quantum systems: (i) isolated iodine molecules in the gas phase, (ii) molecular crystals of para-hydrogen, and (iii) single crystals of bismuth. In system (i), we have controlled and visualized the interference of vibrational wave packets in the isolated iodine molecules, and that wave-packet interference has been utilized to develop a molecular computer, which executes ultrafast Fourier transform. In system (ii), we have manipulated vibrational wave-functions delocalized in a para-hydrogen crystal. The long coherence lifetime of para-hydrogen crystals is a promising resource to preserve quantum information in bulk solids. In system (iii), we have controlled the excitation ratio of two orthogonal coherent phonon modes, whose coherent superposition has allowed for active control of ultrafast two-dimensional atomic motions in a single crystal of bismuth. Those atomic motions have been visualized by density functional theory calculations. Finally, the coherent control of an ensemble of ultracold Rydberg atoms is briefly discussed as future perspectives for exploring the quantum–classical boundary.