Outputs (15)

General upper bounds on fluctuations of trajectory observables (2023)
Journal Article
Bakewell-Smith, G., Girotti, F., Guţǎ, M., & Garrahan, J. P. (2023). General upper bounds on fluctuations of trajectory observables. Physical Review Letters, 131(19), Article 197101. https://doi.org/10.1103/PhysRevLett.131.197101

Thermodynamic uncertainty relations (TURs) are general lower bounds on the size of fluctuations of dynamical observables. They have important consequences, one being that the precision of estimation of a current is limited by the amount of entropy pr... Read More about General upper bounds on fluctuations of trajectory observables.

Projected Least-Squares Quantum Process Tomography (2022)
Journal Article
Surawy-Stepney, T., Kahn, J., Kueng, R., & Guta, M. (in press). Projected Least-Squares Quantum Process Tomography. Quantum, 6, 844. https://doi.org/10.22331/q-2022-10-20-844

We propose and investigate a new method of quantum process tomography (QPT) which we call projected least squares (PLS). In short, PLS consists of first computing the least-squares estimator of the Choi matrix of an unknown channel, and subsequently... Read More about Projected Least-Squares Quantum Process Tomography.

Large deviations, central limit, and dynamical phase transitions in the atom maser (2022)
Journal Article
Girotti, F., Van Horssen, M., Carbone, R., & Guţa, M. (2022). Large deviations, central limit, and dynamical phase transitions in the atom maser. Journal of Mathematical Physics, 63(6), Article 062202. https://doi.org/10.1063/5.0078916

The theory of quantum jump trajectories provides a new framework for understanding dynamical phase transitions in open systems. A candidate for such transitions is the atom maser, which for certain parameters exhibits strong intermittency in the atom... Read More about Large deviations, central limit, and dynamical phase transitions in the atom maser.

Parameter estimation and system identification for continuously-observed quantum systems (2022)
Journal Article
Nurdin, H. I., & Guţǎ, M. (2022). Parameter estimation and system identification for continuously-observed quantum systems. Annual Reviews in Control, 54, 295-304. https://doi.org/10.1016/j.arcontrol.2022.04.012

This paper gives an overview of parameter estimation and system identification for quantum input–output systems by continuous observation of the output field. We present recent results on the quantum Fisher information of the output with respect to u... Read More about Parameter estimation and system identification for continuously-observed quantum systems.

Fast state tomography with optimal error bounds (2020)
Journal Article
Guta, M., Kahn, J., Kueng, R., & Tropp, J. A. (2020). Fast state tomography with optimal error bounds. Journal of Physics A: Mathematical and Theoretical, 53(20), Article 204001. https://doi.org/10.1088/1751-8121/ab8111

Projected least squares is an intuitive and numerically cheap technique for quantum state tomography: compute the least-squares estimator and project it onto the space of states. The main result of this paper equips this point estimator with rigorous... Read More about Fast state tomography with optimal error bounds.

A comparative study of estimation methods in quantum tomography (2019)
Journal Article
Acharya, A., Kypraios, T., & Guta, M. (2019). A comparative study of estimation methods in quantum tomography. Journal of Physics A: Mathematical and Theoretical, 52(23), 1-36. https://doi.org/10.1088/1751-8121/ab1958

As quantum tomography is becoming a key component of the quantum engineering toolbox, there is a need for a deeper understanding of the multitude of estimation methods available. Here we investigate and compare several such methods: maximum likelihoo... Read More about A comparative study of estimation methods in quantum tomography.

Local asymptotic equivalence of pure states ensembles and quantum Gaussian white noise (2018)
Journal Article
Butucea, C., Guţă, M., & Nussbaum, M. (2018). Local asymptotic equivalence of pure states ensembles and quantum Gaussian white noise. Annals of Statistics, 46(6B), 3676-3706. https://doi.org/10.1214/17-aos1672

Quantum technology is increasingly relying on specialised statistical inference methods for analysing quantum measurement data. This motivates the development of “quantum statistics”, a field that is shaping up at the overlap of quantum physics and “... Read More about Local asymptotic equivalence of pure states ensembles and quantum Gaussian white noise.

Minimax estimation of qubit states with Bures risk (2018)
Journal Article
Acharya, A., & Guţă, M. (2018). Minimax estimation of qubit states with Bures risk. Journal of Physics A: Mathematical and Theoretical, 51(17), 1-27. https://doi.org/10.1088/1751-8121/aab6f2

The central problem of quantum statistics is to devise measurement schemes for the estimation of an unknown state, given an ensemble of n independent identically prepared systems. For locally quadratic loss functions, the risk of standard procedures... Read More about Minimax estimation of qubit states with Bures risk.

Information geometry and local asymptotic normality for multi-parameter estimation of quantum Markov dynamics (2017)
Journal Article
Guţă, M., & Kiukas, J. (in press). Information geometry and local asymptotic normality for multi-parameter estimation of quantum Markov dynamics. Journal of Mathematical Physics, 58, https://doi.org/10.1063/1.4982958

This paper deals with the problem of identifying and estimating dynamical parameters of continuous-time Markovian quantum open systems, in the input-output formalism. First, we characterise the space of identifiable parameters for ergodic dynamics, a... Read More about Information geometry and local asymptotic normality for multi-parameter estimation of quantum Markov dynamics.

Statistical analysis of compressive low rank tomography with random measurements (2017)
Journal Article
Acharya, A., & Guţă, M. (in press). Statistical analysis of compressive low rank tomography with random measurements. Journal of Physics A: Mathematical and Theoretical, 50(19), https://doi.org/10.1088/1751-8121/aa682e

We consider the statistical problem of 'compressive' estimation of low rank states (r«d ) with random basis measurements, where r, d are the rank and dimension of the state respectively. We investigate whether for a fixed sample size N, the estimatio... Read More about Statistical analysis of compressive low rank tomography with random measurements.