I am completing my PhD in Physics on circuit quantum electrodynamics (cQED). I focus particularly on quantum vacuum phenomena, which can be observed in superconducting qubits systems as the dynamical Casimir effect and the dynamical Lamb effect. I completed my Bachelor’s degree in Physics Engineering from Politecnico di Milano and my Master’s degree in Physics from the University of Milan in Italy. In August of 2016, I came to the United States to complete my doctoral studies in New York City. My advisor is Professor Roman Kezerashvili (New York City College of Technology).

Project

When a system is perturbed at time scales much shorter than its reaction time, interesting phenomena may appear. The dynamical Lamb effect (DLE) is an example of such phenomena. This refers to the excitation of an atom in a cavity when its Lamb shift is suddenly changed. In cases where there is more than one atom in a cavity, the DLE can generate entanglement (quantum correlation) between them.

This summer, thanks to the support received from the Raucci fellowship, I participated in the Boulder School for Condensed Matter and Material Physics on Quantum Information. This series of seminars, which lasted for a month, provided courses given by international experts in their field in several areas of quantum information. I was able to deepen my understanding of the theoretical aspects of quantum entanglement and superconducting circuit systems, which are an important focus of my research. Superconducting circuits are electrical circuits similar to the ones which can be found in any electrical device. They are constructed by putting together elements like capacitors, resistors, inductors and so on. The difference is that they are made with a material which is capable of transporting current through the circuit without any loss, when cooled to very low temperatures.

In this low temperature regime, the behavior of these circuits cannot be described with the familiar laws of electricity but with quantum mechanics, the most recent theory of physical phenomena. Among the strange features of quantum mechanics is quantum entanglement. This is a connection between objects which arises because of their quantum nature. If two objects are entangled, they will behave much like a single entity. Their behavior will be related, regardless of the distance separating them. It is possible for elements of superconducting circuits to become entangled, and the strength of the correlations which arise between them because of their entanglement can be measured.

In my research, I explore new ways of generating quantum entanglement between elements of superconducting circuits and how this can be turned into a useful resource. Thanks to the rich cultural environment of the school, I had the chance to discuss the details of my investigations with other researchers, both experts and peers, who were able to provide feedback and suggestions on which direction to undertake in the future. Furthermore, during the summer I focused on the development of numerical techniques which provide a way to compare the results found theoretically, giving independent confirmation of the validity of the theoretical framework used. This led to the work currently under review in the journal Physical Review A ^[i], which expanded on previous work ^[ii] to include a more realistic description of the superconducting circuit system studied.

I took fundamental steps in laying the groundwork for my dissertation during the summer. Building on what I learned at the Boulder School, I identified the direction I would like to follow. I aim to provide strong foundations to our work by deriving the parameters of the circuit we are interested from first principles, without using a simplified model. In this way, we will come closer to the experimental setting. We will be able to give experimentalists the specific details of the superconducting circuit which they need to build in order to observe the phenomena we investigate theoretically.

[i] M. Amico, O. L. Berman, R. Ya. Kezerashvili, “Time evolution of the quantum entanglement between N qubits due to dynamical Lamb effect in the presence of dissipation”, arXiv:1806.07126

[ii] M. Amico, O. L. Berman, R. Ya. Kezerashvili, “Tunable quantum entanglement of three qubits in a non-stationary cavity”, Phys. Rev. A 96, 032328.