Sub-system quantum dynamics using coupled cluster downfolding techniques

Ab initio quantum dynamics using coupled-cluster.

The curse of dimensionality (COD) limits the current state-of-the-art ab initio propagation methods for non-relativistic quantum mechanics to relatively few particles. For stationary structure calculations, the coupled-cluster (CC) method overcomes the COD in the sense that the method scales polynomially with the number of particles while still being size-consistent and extensive. We generalize...

Time-dependent coupled-cluster approach to many-body quantum dynamics

The curse of dimensionality severely limits the application of standard basis-expansion methods for solving the time-dependent Schrd̈inger equation: the number of discrete degrees of freedom grows combinatorially with the number of grid points or single-particle basis functions. We therefore propose to use a time-dependent formulation of the highly successful coupledcluster (CC) method used in e...

Quantum dynamics of the dissipative two-state system coupled with a sub-Ohmic bath

The decoherence of a two-state system coupled with a sub-Ohmic bath is investigated theoretically by means of the perturbation approach based on a unitary transformation. It is shown that the decoherence depends strongly and sensitively on the structure of environment. Nonadiabatic effect is treated through the introduction of a function ξk which depends on the boson frequency and renormalized ...

Dynamics of entangled quantum optical system in independent media

We study the dynamics of two three-level atoms interacting with independent bosonic Lorentzian reservoirs at zero temperature. Such systems can be created in far astronomical objects. Quantum mechanical behaviour of these particles can produce detectable effects on the spectroscopic identifications of these objects, if such behaviour remain stable during the interaction with their media. It is ...

Coupled Cluster methods in quantum chemistry