Second Quantization Approach to COVID-19 Epidemic

In this article, a stochastic SIR-type model for COVID-19 epidemic is built using the standard field theoretical language based on creation and annihilation operators. From the model, we derive the time evolution of the mean number of infectious (active cases) and deceased individuals. In order to capture the effects of lockdown and social distancing, we use a time-dependent infection rate. The results are in good agreement with the data for three different waves of epidemic activity in South Korea.

Entanglement and Non-Locality in Quantum Protocols with Identical Particles

We study the role of entanglement and non-locality in quantum protocols that make use of systems of identical particles. Unlike in the case of distinguishable particles, the notions of entanglement and non-locality for systems whose constituents cannot be distinguished and singly addressed are still debated. We clarify why the only approach that avoids incongruities and paradoxes is the one based on the second quantization formalism, whereby it is the entanglement of the modes that can be populated by the particles that really matters and not the particles themselves. Indeed, by means of a metrological and of a teleportation protocol, we show that inconsistencies arise in formulations that force entanglement and non-locality to be properties of the identical particles rather than of the modes they can occupy. The reason resides in the fact that orthogonal modes can always be addressed while identical particles cannot.

Algebra of Superalgebraic Spinors as Algebra of Second Quantization of Fermions

We developed the theory of superalgebraic spinors, which is based on the use of Grassmann densities and derivatives with respect to them in a pseudo-continuous space of momenta. The algebra that they form corresponds to the algebra of second quantization of fermions. We have constructed a vacuum state vector and have shown that it is symmetric with respect to $P$, $CT$ and $CPT$ transformations. Operators $C$ and $T$ transforms the vacuum into an alternative one. Therefore, time inversion $T$ and charge conjugation $C$ cannot be exact symmetries of the spinors.

Characterization of the internal state of NV center in diamond and second quantization formalism

In this paper a general study of NV center internal state in diamond is presented. This study is based on experimental and theoretical findingsfound in literature. First, a Hamiltonian model for center NV internal state is proposed in terms of a complete set of commuting observables(CSCO), which consist of angular momentum ^L, spin momentum ^ S, total angular momentum ^ J = ^L+ ^ S and spin momentum on z-direction^ Sz. The second quantization formalism –in steady-state (conservative model)– is used. The creation and annihilation operators are used todescribed the steady spin-levels structure and in dynamic-state (non-conservative model) and can also describe the system dynamic betweendifferent spin-levels transitions. Finally, a discussion is presented about the application of this study in the photochromism phenomenon andsolid-state quantum bit (qubit).