Optimal Cold Atom Thermometry Using Adaptive Bayesian Strategies

Glatthard, Jonas; Rubio, Jesús; Sawant, Rahul; Hewitt, Thomas E.; Barontini, Giovanni; Correa, Luis Alfonso

doi:10.1103/prxquantum.3.040330

Cited by 14 publications

(6 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…with Z := Tre −(HB−µN)/T being the partition function, and N := q b † q b q . As for the probe, we consider a single fermionic mode-extension to multiple fermionic modes is discussed later in section [6]. Let the Hamiltonian of the probe be…”

Section: Resonant Level Modelmentioning

confidence: 99%

“…Estimating the temperature of quantum systems is challenging but crucial; temperature appears as a relevant parameter in the Gibbs state of quantum systems even if they evolve unitarily [1][2][3]. The growing field of quantum thermometry is dedicated to developing cutting edge experimental protocols for reading out the temperature of cold systems operating at the quantum regime [4][5][6][7]. It is also devoted to investigating the fundamental bounds on achievable precision that are set by quantum physics through Cramér-Rao inequalities [8,9].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Strongly coupled fermionic probe for nonequilibrium thermometry

Ravell Rodríguez,

Mehboudi,

Horodecki

et al. 2024

New J. Phys.

View full text Add to dashboard Cite

We characterise the measurement sensitivity, quantified by the Quantum Fisher Information (QFI), of a single-fermionic thermometric probe strongly coupled to the sample of interest, a fermionic bath, at temperature T. For nonequilibrium protocols, in which the probe is measured before reaching equilibrium with the sample, we find new behaviour of the measurement sensitivity arising due to non-Markovian dynamics. First, we show that the QFI displays a highly non-monotonic behaviour in time, in contrast to the Markovian case where it grows monotonically until equilibrium, so that non-Markovian revivals can be exploited to reach a higher QFI. Second,the QFI rate is maximised at a finite interrogation time t, which we characterize, in contrast to the solution t→0 known in the Markovian limit [Quantum 6, 869 (2022)]. Finally, we consider probes make up of few fermions and discuss different collective enhancements in the measurement precision.

show abstract

Section: Resonant Level Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Strongly coupled fermionic probe for nonequilibrium thermometry

Ravell Rodríguez,

Mehboudi,

Horodecki

et al. 2024

New J. Phys.

View full text Add to dashboard Cite

show abstract

“…In order to avoid undesired light shifts caused by the SST, we chop the fluorescence and tweezer light at a frequency of 1.02 MHz and a phase shift of 90 • [43]. To measure the temperature of the K atoms, we perform release-recapture thermometry using Bayesian estimation, requiring 180 experimental runs [44].…”

Section: Realization Of a K Quantum Impurity In A Rb Thermal Bathmentioning

confidence: 99%

Controlling the interactions in a cold atom quantum impurity system

Hewitt,

Bertheas,

Jain

et al. 2024

Quantum Sci. Technol.

Self Cite

View full text Add to dashboard Cite

We implement an experimental architecture in which a single atom of K is trapped in an optical tweezer, and is immersed in a bath of Rb atoms at ultralow temperatures. In this regime, the motion of the single trapped atom is confined to the lowest quantum vibrational levels. This realizes an elementary and fully controllable quantum impurity system. For the trapping of the K atom, we use a species-selective dipole potential, that allows us to independently manipulate the quantum impurity and the bath. We concentrate on the characterization and control of the interactions between the two subsystems. To this end, we perform Feshbach spectroscopy, detecting several inter-dimensional confinement-induced Feshbach resonances for the KRb interspecies scattering length, that parametrizes the strength of the interactions. We compare our data to a theory for inter-dimensional scattering, finding good agreement. Notably, we also detect a series of p-wave resonances stemming from the underlying free-space s-wave interactions. We further determine how the resonances behave as the temperature of the bath and the dimensionality of the interactions change. Additionally, we are able to screen the quantum impurity from the bath by finely tuning the wavelength of the light that produces the optical tweezer, providing us with a new effective tool to control and minimize the interactions. Our results open a range of new possibilities in quantum simulations of quantum impurity models, quantum information, and quantum thermodynamics, where the interactions between a quantized system and the bath is a powerful yet largely underutilized resource.

show abstract

“…In figure 2 we depict a Monte-Carlo simulation of the relative error for the optimal estimator [c.f. equation (28)] in this non-adaptive scenario for a bosonic bath.…”

Section: Strategymentioning

confidence: 99%

“…Relevant experimental realization of probe thermometry include single-atom probes for ultracold gases [7][8][9], NV centers acting as thermometers of living cells [10,11], and nanoscale electron calorimeters [12][13][14]. Theoretically, much progress has been achieved on characterizing the fundamental precision limits of probe thermometry in frequentist and Bayesian approaches [15][16][17][18][19][20][21][22][23], the precision scaling at ultralow temperatures [24][25][26][27][28], the impact of strong coupling and correlations [29][30][31][32][33][34], measurement back action [35,36], as well as enhanced sensing via non-equilibrium probes [37][38][39][40][41][42][43][44][45][46]. While providing remarkable progress on our understanding of thermometry, previous works are based on the assumption that the probe is measured and subsequently reset or discarded.…”

Section: Introductionmentioning

confidence: 99%

Probe thermometry with continuous measurements

Boeyens,

Annby-Andersson,

Bakhshinezhad

et al. 2023

New J. Phys.

View full text Add to dashboard Cite

Temperature estimation plays a vital role across natural sciences. A standard approach is provided by probe thermometry, where a probe is brought into contact with the sample and examined after a certain amount of time has passed. In situations where, for example, preparation of the probe is non-trivial or total measurement time of the experiment is the main resource that must be optimized, continuously monitoring the probe may be preferred. Here, we consider a minimal model, where the probe is provided by a two-level system coupled to a thermal reservoir. Monitoring thermally activated transitions enables real-time estimation of temperature with increasing accuracy over time. Within this framework we comprehensively investigate thermometry in both bosonic and fermionic environments employing a Bayesian approach. Furthermore, we explore adaptive strategies and find a significant improvement on the precision. Additionally, we examine the impact of noise and find that adaptive strategies may suffer more than non-adaptive ones for short observation times. While our main focus is on thermometry, our results are easily extended to the estimation of other environmental parameters, such as chemical potentials and transition rates.

show abstract

Optimal Cold Atom Thermometry Using Adaptive Bayesian Strategies

Cited by 14 publications

References 53 publications

Strongly coupled fermionic probe for nonequilibrium thermometry

Strongly coupled fermionic probe for nonequilibrium thermometry

Controlling the interactions in a cold atom quantum impurity system

Probe thermometry with continuous measurements

Contact Info

Product

Resources

About