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| Author(s): |
Gabriel Oliveira Alves
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Física (IF/SBI) |
| Defense date: | 2023-02-06 |
| Examining board members: |
Luis Gregorio Godoy de Vasconcellos Dias da Silva;
Fabrício de Souza Luiz;
Saulo Vicente Moreira
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| Advisor: | Gabriel Teixeira Landi |
| Abstract | |
In this thesis we deal with two different topics. In the first half we investigate how the Bayesian formalism can be introduced into the problem of quantum thermometry a field which exploits the high level of control in coherent devices to offer enhanced precision for temperature estimation. In particular, we investigate concrete estimation strategies, with focus on collisional thermometry, a protocol where a series of ancillae are sent sequentially to probe the systems temperature. We put forth a complete framework for analyzing collisional thermometry using Bayesian inference. The approach is easily implementable and experimentally friendly. Moreover, it is guaranteed to always saturate the Cramér-Rao bound in the long-time limit. Subtleties concerning the prior information about the systems temperature are also discussed and analyzed in terms of a modified Cramér-Rao bound associated with Van Trees and Schützenberger. Meanwhile, in the last part of the thesis we approach the problem of non-adiabatic holonomic computation. Namely, we investigate the implementation based on -systems. It is known that a three-level system can be used in a -type configuration in order to construct a universal set of quantum gates through the use of non-Abelian nonadiabatic geometrical phases. Such construction allows for high- speed operation times which di- minish the effects of decoherence. This might be, however, accompanied by a breakdown of the validity of the rotating-wave approximation (RWA) due to the comparable timescale between counter-rotating terms and the pulse length, which greatly affects the dynamics. Here, we investigate the trade-off between dissipative effects and the RWA validity, ob- taining the optimal regime for the operation of the holonomic quantum gates. (AU) | |
| FAPESP's process: | 20/16050-0 - Stroboscopic quantum metrology |
| Grantee: | Gabriel Oliveira Alves |
| Support Opportunities: | Scholarships in Brazil - Master |