arXiv subjects

Guilherme Temporão

Publications and source records attributed to Guilherme Temporão.

5 recordsLinked to original sources

arXiv2024

All electrical cooling of an optically levitated nanoparticle

We implement an all electrical controller for 3D feedback cooling of an optically levitated nanoparticle capable of reaching sub-Kelvin temperatures for the center of mass motion. The controller is based on an optimal policy where state estimation is made by delayed position measurements. The method offers a simplified path for pre-cooling and decoupling the transverse degrees of freedom of the nanoparticle. Numerical simulations show that in an improved setup with quantum limited detection, 3D ground state cooling and all electrical quantum control can be achieved.

quant-ph↗

arXiv2023

Perturbative nonlinear feedback forces for optical levitation experiments

Feedback control can be used to generate well-determined nonlinear effective potentials in an optical trap, a goal whose applications may range from non-equilibrium thermodynamics to the generation of non-Gaussian states of mechanical motion. Here, we investigate the action of an effective feedback-generated quartic potential on a levitated nanoparticle within the perturbation regime. The effects of feedback delay are discussed and predictions from the perturbation theory of a Brownian particle subjected to a quartic anharmonicity are experimentally verified.

quant-ph↗

arXiv2022

Swap Test-based Characterization of Quantum Processes in Universal Quantum Computers

Quantum Computing has been presenting major developments in the last few years, unveiling systems with a increasing number of qubits. However, unreliable quantum processes in universal quantum computers still represent one of the the greatest challenges to be overcome. Such obstacle has its source on noisy operations and interactions with the environment which introduce decoherence to a quantum system. In this article we verify whether a tool called Swap Test is able to identify decoherence. Our experimental results demonstrate that the Swap Test can be employed as an alternative to a full Quantum Process Tomography, with the advantage of not destroying the qubit under test, under certain circumstances, as long as some modifications are introduced.

quant-ph↗

arXiv2020

Relaxing constraints on data acquisition and position detection for trap stiffness calibration in optical tweezers

Optical tweezers find applications in various fields, ranging from biology to physics. One of the fundamental steps necessary to perform quantitative measurements using trapped particles is the calibration of the tweezer's spring constant. This can be done through power spectral density analysis, from forward scattering detection of the particle's position. In this work, we propose and experimentally test simplifications to such measurement procedure, aimed at reducing post-processing of recorded data and dealing with acquisition devices that have frequency-dependent electronic noise. In the same line of simplifying the tweezer setup, we also present a knife-edge detection scheme that can substitute standard position-sensitive detectors.

quant-ph↗

arXiv2019

Alignment-free characterization of polarizing beamsplitters

Traditional methods for measurement of Polarizing Beamsplitter (PBS) parameters, especially the extinction ratio, require highly polarized light sources, alignment procedures and/or experimental parameters that change over time, such as polarization rotations. In this work, a new method is presented, which employs unpolarized light and a Faraday Mirror. It is shown that precise extinction ratio and insertion loss values can be achieved in three single-sweep measurements, without any alignment requirements or time-varying signals of any kind.

physics.optics↗