Quantum entanglement between electronic and vibrational degrees of freedom in molecules

Abstract

We consider the quantum entanglement of the electronic and vibrational degrees of freedom in molecules with a tendency towards double welled potentials using model coupled harmonic diabatic potential-energy surfaces. The von Neumann entropy of the reduced density matrix is used to quantify the electron-vibration entanglement for the lowest two vibronic wavefunctions in such a bipartite system. Significant entanglement is found only in the region in which the ground vibronic state contains a density profile that is bimodal (i.e., contains two separate local minima). However, in this region two distinct types of entanglement are found: (1) entanglement that arises purely from the degeneracy of energy levels in the two potential wells and which is destroyed by slight asymmetry, and (2) entanglement that involves strongly interacting states in each well that is relatively insensitive to asymmetry. These two distinct regions are termed fragile degeneracy-induced entanglement and persistent entanglement, respectively. Six classic molecular systems describable by two diabatic states are considered: ammonia, benzene, semibullvalene, pyridine excited triplet states, the Creutz-Taube ion, and the radical cation of the "special pair" of chlorophylls involved in photosynthesis. These chemically diverse systems are all treated using the same general formalism and the nature of the entanglement that they embody is elucidated.

References in corpus (10)

• Beyond the Jaynes-Cummings model: circuit QED in the ultrastrong coupling regime
• Hund's paradox and the collisional stabilization of chiral molecules
• Chirality Quantum Phase Transition in the Dirac oscillator
• Quantum entanglement between electronic and vibrational degrees of freedom in molecules
• Universal and measurable entanglement entropy in the spin-boson model
• Variational study of a two-level system coupled to a harmonic oscillator in a ultrastrong coupling regime
• Jahn-Teller systems from a cavity QED perspective
• Entanglement Dynamics in a Dispersively Coupled Qubit-Oscillator System
• Classical bifurcations and entanglement in smooth Hamiltonian system
• Charge transfer and coherence dynamics of tunnelling system coupled to a harmonic oscillator

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• The correlation theory of the chemical bond
• Disorder enhanced vibrational entanglement and dynamics in polaritonic chemistry
• Quantum phenomena in attosecond science
• Unified description of hydrogen bonding and of proton transfer by a two-state effective Hamiltonian
• Entanglement between electronic and vibrational degrees of freedom in a laser-driven molecular system
• Quantum information-based analysis of electron-deficient bonds
• Two-Frequency Jahn-Teller Systems in Circuit QED
• Beyond the one-dimensional configuration coordinate model of photoluminescence
• A diabatic state model for double proton transfer in hydrogen bonded complexes
• Quantum Correlations in Jahn-Teller Molecular Systems Simulated with Superconducting Circuits