## Duarte Magano

Physics of Information and Quantum Technologies Group, Instituto de Telecomunicações

PhD Student in Physics, Instituto Superior Técnico - Lisbon

### Second QuantHEP Workshop

The second workshop of project QuantHEP – Quantum Computing Solutions for High-Energy Physics has taken place on 18-19 May 2020, online. I gave a presentation on our work on quantum algorithms for particle tracking.

### Workshop on New Development in the Physics of Information and in Quantum Technologies

The Physics of Information and Quantum Technologies Group has gone on a 2-day retreat at Convento da Arrábida. I have presented an overview of my work in a talk entitled "Quantum Simulation: Overcoming the Curse of Hilbert Space".

I have been a theoretical physicist of some sort since the day I was born. Throughout my career I’ve worked in a variety subjects, from astrophysics and cosmology to quantum optics and condensed matter (see research projects bellow). But I am interested in every part of physics.

Now I’m starting a PhD in quantum computation and simulation at the Physics of Information and Quantum Technologies Group (Instituto Superior Técnico, Lisbon).

## Education:

See full CV.

## Research Projects

The flow equation approach to quantum systems is an iterative method to diagonalise Hamiltonians which has recently been finding more and more applications in many-body problems.

We succeeded in generalizing this method to time-dependent systems.

*(this is a work in progress)*

We proposed a physical scheme to generate entangled light at high temperatures through the excitation of vacuum fluctuations of the electromagnetic field using periodic modulations of a refractive index of a ring resonator.

In our model we consider the processes of dissipation and decoherence resulting from the coupling of the system with an environment at finite temperature and found that the total amount of entanglement generated does not depend on the temperature. In fact, it only affects the time necessary for the system to produce such an amount of entanglement.

Mapping the behaviour of dark energy is a pressing task of observational cosmology. A phenomenological classification divides dynamical dark energy models into freezing and thawing, depending on whether the dark energy equation of state is approaching or moving away from w = p/ρ = −1. Moreover, in realistic dynamical dark energy models the dynamical degree of freedom is expected to couple to the electromagnetic sector, leading to variations of the fine-structure constant α (like in this figure).

In this work we discussed the feasibility of distinguishing between the freezing and thawing classes of models with current and forthcoming observational facilities, using as fiducial paradigm a parametrisation of the dark energy equation of state introduced by Mukhanov which can have either behaviour.

We illustrated how freezing and thawing models lead to different redshift dependencies of α, and use a combination of current astrophysical observations and local experiments to constrain this class of models.

We also briefly discussed the improvements expected from future facilities, and comment on the practical limitations of this class of parametrisations.

In this project we studied the feasibility of using astrophysical observations of white dwarfs as probes of fundamental physics.

We quantified the effects of varying fundamental couplings on the white dwarf mass-radius relation in a broad class of unification scenarios, both for the simple case of a polytropic stellar structure model and for more general models.

Using independent measurements of the mass and radius, together with direct spectroscopic measurements of the fine-structure constant in white dwarf atmospheres we found constraints on combinations of the two phenomenological parameters describing the underlying unification scenario (one of which is related to the strong sector of the theory while the other is related to the electroweak sector).

See arxiv version.

## Publications

- Hight temperature generation of entangled light in parametrically excited micro and nano-ring ressonators for integrated optics. PAM Macedo, DMN Magano, A Guerreiro - to be published.
- Distinguishing freezing and thawing dark energy models through measurements of the fine-structure constant. JMA Vilas Boas, DMNM Magano, CJAP Martins, A Barbecho, C Serrano - Astronomy & Astrophysics, 2020.
- Current and future white dwarf mass-radius constraints on varying fundamental couplings and unification scenarios. DMN Magano, JMA Vilas Boas, CJAP Martins - Physical Review D, 2017.

## Contact

Official email: duartemagano@tecnico.ulisboa.pt