Chapter 6
Coherent Control of Nonadiabatic
Dynamics of Electron-Phonon Systems
by Quantized Light Field
Kunio Ishida
Abstract Coherent control of electron-phonon systems is studied by numerical calculations on a toy model. We found that the interplay of the electron-phonon nonadiabaticity and the Raman scattering determines the wavepacket motion particularly
in the vicinity of the conical intersection of adiabatic potential energy surfaces.
Entanglement between photons, phonons, or electrons is discussed by calculating
the entanglement entropy. We showed that the quantum nature of irradiated light
plays an important role in considering design and/or manipulation methods of the
quantum-mechanical states of electron-phonon systems in coherent regime.
6.1 Introduction
Coherent control of quantum-mechanical states have been studied since the proposal of the adaptive control method [1], which are considered to be promising for
innovative technology particularly in the field of quantum information. For example,
recent experiments on diamond showed the possibility of phonon-mediated coherence between qubits via Raman scattering processes [2]. In this case, entanglement
between electrons, phonons, and photons plays an important role, which means that
theory of quantum entanglement between irradiated light and materials is necessary
to reveal and/or design the control methods for them. In other words, we should
study the quantum dynamics of the full Hamiltonian regarding all the above entities
as quantum variables, taking into account the interplay among electrons, photons,
and phonons.
On the other hand, recent progress of ultrashort pulse laser technology has made it
possible to observe time evolution of quantum-mechanical states in coherent regime.
Above all, time-resolved techniques have been developed to clarify the excited-state
dynamics of condensed matter, and its transient properties have been studied [3–6].
K. Ishida (B)
School of Engineering, Utsunomiya University, 7-1-2 Yoto,
Utsunomiya, Tochigi 321-8585, Japan
e-mail: ishd_kn@cc.utsunomiya-u.ac.jp
© Springer Nature Switzerland AG 2020
K. Yamanouchi and D. Charalambidis (eds.), Progress in Ultrafast
Intense Laser Science XV, Topics in Applied Physics 136,
https://doi.org/10.1007/978-3-030-47098-2_6
121
Coherent Control of Nonadiabatic
Dynamics of Electron-Phonon Systems
by Quantized Light Field
Kunio Ishida
Abstract Coherent control of electron-phonon systems is studied by numerical calculations on a toy model. We found that the interplay of the electron-phonon nonadiabaticity and the Raman scattering determines the wavepacket motion particularly
in the vicinity of the conical intersection of adiabatic potential energy surfaces.
Entanglement between photons, phonons, or electrons is discussed by calculating
the entanglement entropy. We showed that the quantum nature of irradiated light
plays an important role in considering design and/or manipulation methods of the
quantum-mechanical states of electron-phonon systems in coherent regime.
6.1 Introduction
Coherent control of quantum-mechanical states have been studied since the proposal of the adaptive control method [1], which are considered to be promising for
innovative technology particularly in the field of quantum information. For example,
recent experiments on diamond showed the possibility of phonon-mediated coherence between qubits via Raman scattering processes [2]. In this case, entanglement
between electrons, phonons, and photons plays an important role, which means that
theory of quantum entanglement between irradiated light and materials is necessary
to reveal and/or design the control methods for them. In other words, we should
study the quantum dynamics of the full Hamiltonian regarding all the above entities
as quantum variables, taking into account the interplay among electrons, photons,
and phonons.
On the other hand, recent progress of ultrashort pulse laser technology has made it
possible to observe time evolution of quantum-mechanical states in coherent regime.
Above all, time-resolved techniques have been developed to clarify the excited-state
dynamics of condensed matter, and its transient properties have been studied [3–6].
K. Ishida (B)
School of Engineering, Utsunomiya University, 7-1-2 Yoto,
Utsunomiya, Tochigi 321-8585, Japan
e-mail: ishd_kn@cc.utsunomiya-u.ac.jp
© Springer Nature Switzerland AG 2020
K. Yamanouchi and D. Charalambidis (eds.), Progress in Ultrafast
Intense Laser Science XV, Topics in Applied Physics 136,
https://doi.org/10.1007/978-3-030-47098-2_6
121