0000000000267755
AUTHOR
S. Nicolosi
An Operator-Based Exact Treatment of Open Quantum Systems
"Quantum mechanics must be regarded as open systems. On one hand, this is due to the fact that, like in classical physics, any realistic system is subjected to a coupling to an uncontrollable environment which influences it in a non-negligible way. The theory of open quantum systems thus plays a major role in many applications of quantum physics since perfect isolation of quantum system is not possible and since a complete microscopic description or control of the environment degrees of freedom is not feasible or only partially so" [1]. Practical considerations therefore force one to seek for a simpler, effectively probabilistic description in terms of an open system. There is a close physi…
Proposal validation of a phenomenoogical model for predicting the vehicular environmental impact
Pollutant concentrations in urban canyon mainly come from vehicular emissions. The search of a quantitative relationship, linking pollutant emissions from mobile sources to the resulting concentrations, at different receptor sites, has brought us to develop a phenomenological model able to calculate the number of running vehicles once the pollutant ground level concentration of CO is known. Unfortunately, we haven't the possibility to test this model by a direct inspection of the traffic flow. Despite this fact it is our aim to validate the proposed traffic model. Mathematical models are considered useful tools in supporting air quality evaluations. The structure of the models usually embod…
Quantum Computation in a radio single mode cavity: the dissipative Jaynes and Cummings Model
In this paper we have considered the interaction of a Jaynes and Cummings system with the electromagnetic field in its vacuum state and, solving the dynamical problem, we have analyzed the amount of entanglement induced in the bipartite system (atom + cavity mode) by the common electromagnetic reservoir. This has allowed us to quantitatively characterize the regime under which field-induced cooperative effects are not vanished by dissipation. Once the Decoherence Free Regime is reached, transient entanglement tends to become stationary and, therefore, usable for quantum gate implementation.
Relationships between pollutant emissions from vehicles and levels of concentrations: a phenomenological approach
The level of air quality in urban centres is affected by emission of several pollutants, mainly coming from the vehicles flowing in their road networks. This is a well known phenomenon that influences the quality of life of people. Despite the deep concern of researchers and technicians, we are far from a total understanding of this phenomenon. On the contrary, the availability of reliable forecasting models would constitute an important tool for administrators in order of assessing suitable actions concerning the transportation policies, public as well private. As matter of fact, the definition of a physical model requires the knowledge of many parameters, involving the running fleet, the …
Loss induced collective subradiant Dicke behaviour in a multiatom sample
The exact dynamics of $N$ two-level atoms coupled to a common electromagnetic bath and closely located inside a lossy cavity is reported. Stationary radiation trapping effects are found and very transparently interpreted in the context of our approach. We prove that initially injecting one excitation only in the $N$ atoms-cavity system, loss mechanisms asymptotically drive the matter sample toward a long-lived collective subradiant Dicke state. The role played by the closeness of the $N$ atoms with respect to such a cooperative behavior is brought to light and carefully discussed.
Dissipation-induced stationary entanglement in dipole-dipole interacting atomic samples
The dynamics of two two-level dipole-dipole interacting atoms coupled to a common electro-magnetic bath and closely located inside a lossy cavity, is reported. Initially injecting only one excitation in the two-atom cavity system, loss mechanisms asymptotically drive the matter sample toward a stationary maximally entangled state. The role played by the closeness of the two atoms, with respect to such a cooperative behavior, is carefully discussed. Stationary radiation trapping effects are found and transparently interpreted.
A new mathematical tool for an exact treatment of open quantum system dynamics
A new method to obtain an operatorial exact solution of a wide class of Markovian master equations is presented. Its key point is the existence of a constant of motion partitioning the Hilbert space into finite-dimensional subspaces. The consequent possibility of representing the reduced density operator as a block diagonal matrix is shown. Each “block operator” evolves under the action of a non-unitary operator explicitly derived. Our mathematical approach is illustrated applying it to simple physical systems.