The photochemistry of a molecular ensemble coupled to a resonance cavity and triggered by a femtosecond laser pulse is investigated from a real-time, quantum dynamics perspective with the multi-configuration time-dependent Hartree method. Coherent excitation of a superposition of electronic states in the ensemble leads to superradiant energy transfer to the cavity characterized by quadratic scaling with the number of molecules. Electronic decoherence associated with loss of nuclear wave packet overlap among those states destroys superradiant energy transfer, returning to a linear regime. For equal pump laser conditions, the photoexcitation probability per molecule decreases with increase of the number of molecules inside the cavity. This is caused by a loss of resonance condition of the laser with the bright electronic-photonic states of the coupled cavity-ensemble system. Increase of the laser bandwidth restores the energy transferred per molecule and the trigger probability remains independent of the number of molecules in the cavity.
Non-adiabatic Effects Induced by Strong Light-Matter Coupling in Cavity QED
St. Petersburg State University（圣彼得堡国立大学）；Petersburg Nuclear Physics Institute named after B.P. Konstantinov of National Research Centre ’Kurchatov Institut’（鲍里特·康斯坦丁诺夫国家核研究中心圣彼得堡核物理研究所）；D. I. Mendeleev Institute for Metrology（德米特里·门捷列夫计量研究所）
Modeling the non-equilibrium dissipative dynamics of strongly interacting quantized degrees of freedom is a fundamental problem in several branches of physics and chemistry. We implement a quantum state trajectory scheme for solving Lindblad quantum master equations that describe coherent and dissipative processes for a set of strongly-coupled quantized oscillators. The scheme involves a sequence of stochastic quantum jumps with transition probabilities determined the system state and the system-reservoir dynamics. Between consecutive jumps, the wavefunction is propagated in coordinate space u…
Cavity-modified electronic interactions in molecular ensembles under vibrational strong coupling: Combined insights from cavity Born-Oppenheimer perturbation and ab initio wave function theories
The quantum photodynamics of a simple diatomic molecule with a permanent dipole immersed within an optical cavity containing a quantized radiation field is studied in detail. The chosen molecule under study, lithium fluoride (LiF), is characterized by the presence of an avoided crossing between the two lowest $^1Σ$ potential energy curves (covalent-ionic diabatic crossing). Without field, after prompt excitation from the ground state $1\; ^1Σ$, the excited nuclear wave packet moves back and forth in the upper $2\; ^1Σ$ state, but in the proximity of the avoided crossing, the non-adiabatic coup…
We develop a fully quantum mechanical methodology to describe the static properties and the dynamics of a single anharmonic vibrational mode interacting with a quantized infrared cavity field in the strong and ultrastrong coupling regimes. By comparing multiconfiguration time-dependent Hartree (MCTDH) simulations for a Morse oscillator in a cavity, with an equivalent formulation of the problem in Hilbert space, we describe for the first time the essential role of permanent dipole moments in the femtosecond dynamics of vibrational polariton wavepackets. We show that depending on the shape of th…
Quantum dynamics of the photoisomerization of a single 3,3'-diethyl-2,2'-thiacynine iodide molecule embedded in an optical microcavity was theoretically studied. The molecule was coupled to a single cavity mode via the quantum Rabi Hamiltonian, and the corresponding time-dependent Schrödinger equation starting with a purely molecular excitation was solved using the Multiconfigurational Time-Dependent Hartree Method (MCTDH). We show that, for single-molecule strong coupling with the photon mode, nonadiabatic molecular dynamics produces mixing of polariton manifolds with differing number of exci…
