Wigner representation of the rotational dynamics of rigid tops

Zhdanov, Dmitry V.; Seideman, Tamar

doi:10.1103/physreva.92.012129

Cited by 8 publications

(7 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 3 shows the optimization procedure which achieves the infidelity IF = 3.89 × 10 −4 after 24 iterations. We further changed other target operations and also met no any trap in the optimization process, which is consistent with the landscape of quantum system from the practical perspective, saying the traps of optimization are usually avoidable when the time duration is very long [35]. On the other hand, the PWM algorithm achieves a very high precision with only 24 iterations.…”

Section: B 6-qubit Example With 2 Controlssupporting

confidence: 58%

Pulse Width Modulation for Speeding Up Quantum Optimal Control Design

Chen¹,

Wu²

2016

Preprint

View full text Add to dashboard Cite

This paper focuses on accelerating quantum optimal control design for complex quantum systems. Based on our previous work [arXiv:1607.04054], we combine Pulse Width Modulation (PWM) and gradient descent algorithm into solving quantum optimal control problems, which shows distinct improvement of computational efficiency in various cases. To further apply this algorithm to potential experiments, we also propose the smooth realization of the optimized control solution, e.g. using Gaussian pulse train to replace rectangular pulses. Based on the experimental data of the D-Norleucine molecule, we numerically find optimal control functions in 3-qubit and 6-qubit systems, and demonstrate its efficiency advantage compared with basic GRAPE algorithm.

show abstract

Section: B 6-qubit Example With 2 Controlssupporting

confidence: 58%

Pulse Width Modulation for Speeding Up Quantum Optimal Control Design

Chen¹,

Wu²

2016

Preprint

View full text Add to dashboard Cite

show abstract

“…We refer the interested reader to [47] for details. The Wigner representation can also be used to facilitate the analysis of molecular rotational dynamics [48].…”

Section: Free Rotation Of a Moleculementioning

confidence: 99%

Quantum control of molecular rotation

2019

View full text Add to dashboard Cite

The angular momentum of molecules, or, equivalently, their rotation in three-dimensional space, is ideally suited for quantum control. Molecular angular momentum is naturally quantized, time evolution is governed by a well-known Hamiltonian with only a few accurately known parameters, and transitions between rotational levels can be driven by external fields from various parts of the electromagnetic spectrum. Control over the rotational motion can be exerted in one-, two-and many-body scenarios, thereby allowing to probe Anderson localization, target stereoselectivity of bimolecular reactions, or encode quantum information, to name just a few examples. The corresponding approaches to quantum control are pursued within separate, and typically disjoint, subfields of physics, including ultrafast science, cold collisions, ultracold gases, quantum information science, and condensed matter physics. It is the purpose of this review to present the various control phenomena, which all rely on the same underlying physics, within a unified framework. To this end, we recall the Hamiltonian for free rotations, assuming the rigid rotor approximation to be valid, and summarize the different ways for a rotor to interact with external electromagnetic fields. These interactions can be exploited for control -from achieving alignment, orientation, or laser cooling in a one-body framework, steering bimolecular collisions, or realizing a quantum computer or quantum simulator in the many-body setting. IntroductionMolecules, unlike atoms, are extended objects that possess a number of different types of internal motion. In particular, the geometric arrangement of their constituent atoms endows molecules with the basic capability to rotate in three-dimensional space. Rotations can couple to vibrations of the atomic nuclei as well as to the orbital and spin angular momentum of the electrons. The resulting complexity of the energy level structure [1,2,3,4] may be daunting. It offers, on the other hand, a variety of knobs for control and thus is at the core of numerous applications, from the classic example of the ammonia maser [5] all the way to recent measurements of the electron's electric dipole moment in a cryogenic molecular beam of thorium monoxide [6].A key advantage of internal degrees of freedom such as rotation is that they occupy the low-energy part of the energy spectrum. Quantization of the rotational motion has been an early hallmark of quantum mechanics due to its connection to selection rules that govern all light-matter interactions [7]. Nowadays, rotational states and rotational molecular dynamics feature prominently in all active areas of AMO physics research as well as in neighbouring fields such as physical chemistry and quantum information science. Control over the rotational motion is crucial in one-body, two-body and many-body scenarios. For example, rotational state-selective excitation could pave the way towards separating left-and right handed enantiomers of chiral molecules [8,9]. Still within the one-body scenar...

show abstract

“…( 7) and ( 8)). In comparison with the fidelity of different local maximums we see that initial point a = 0 is the valid choice for numerical BFGS search in order to avoid traps [29][30][31][32][33], and our assumption lim T →0 G(T ) = 0 is corroborated. Moreover, the universal initial point (0, 0) (which satisfies (18)) for numerical search connects together adiabatic and non-adiabatic time domains.…”

mentioning

confidence: 53%

Quantum mechanics and speed limit of ultrafast local control in spin chains

Pyshkin

Sherman

2019

Phys. Rev. A

View full text Add to dashboard Cite

We study optimization of fidelity for ultrafast transformation of a spin chain via external control of a local exchange coupling. We show that infidelity of such a process can be dramatically decreased by choosing a proper control profile in nonadiabatic time domain, predict main features of this profile analytically and corroborate them numerically with a gradient search algorithm. This optimal control shape has a universal nature with several features independent of the transformation time. Our result can be applied to control a broad variety of quantum systems.

show abstract

Wigner representation of the rotational dynamics of rigid tops

Cited by 8 publications

References 58 publications

Pulse Width Modulation for Speeding Up Quantum Optimal Control Design

Pulse Width Modulation for Speeding Up Quantum Optimal Control Design

Quantum control of molecular rotation

Quantum mechanics and speed limit of ultrafast local control in spin chains

Contact Info

Product

Resources

About