Ehrenfest ‘phase-space’ trajectories and quantum chaos in He atom under strong, oscillating magnetic fields: an application of time-dependent quantum fluid density functional theory (TDQFDFT)

ABSTRACT

Using a dynamical signature proposed earlier from our laboratory, quantum chaos in He atom interacting with strong, oscillating magnetic fields has been studied through a comparison between the nonlinear divergence of two neighbouring Ehrenfest ‘phase-space’ (EPS) trajectories differing slightly in initial conditions and the Loschmidt echo. The dynamical EPS signature can detect quantum chaos independently of the Loschmidt echo and in agreement with the latter, even for low-lying states, in the same spirit as that of classical chaos. This time-dependent signature extends the concept of quantum chaos to systems which have no classical counterparts and brings the concept of quantum chaos closer to that of classical chaos.

KEYWORDS:

• Ehrenfest phase-space
• quantum chaos
• strong, oscillating magnetic fields
• many-electron systems

Acknowledgments

M. Sadhukhan thanks CSIR, New Delhi and SNBNCBS, Kolkata for financial support. B.M. Deb thanks Indian National Science Academy, New Delhi, for financial support and Visva-Bharati University, Santiniketan, for hospitality.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

CSIR, New Delhi; SNBNCBS, Kolkata; Indian National Science Academy, New Delhi.