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- Bakhshinezhad, Pharnam, et al.
(författare)
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Scalable Entanglement Certification via Quantum Communication
- 2024
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Ingår i: PRX Quantum. - 2691-3399. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Harnessing the advantages of shared entanglement for sending quantum messages often requires the implementation of complex two-particle entangled measurements. We investigate entanglement advantages in protocols that use only the simplest two-particle measurements, namely, product measurements. For experiments in which only the dimension of the message is known, we show that robust entanglement advantages are possible but that they are fundamentally limited by Einstein-Podolsky-Rosen steering. Subsequently, we propose a natural extension of the standard scenario for these experiments and show that it circumvents this limitation. This leads us to prove entanglement advantages from every entangled two-qubit Werner state, evidence its generalization to high-dimensional systems, and establish a connection to quantum teleportation. Our results reveal the power of product measurements for generating quantum correlations in entanglement-assisted communication and they pave the way for practical semi-device-independent entanglement certification well beyond the constraints of Einstein-Podolsky-Rosen steering.
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| 2. |
- Boeyens, Julia, et al.
(författare)
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Probe thermometry with continuous measurements
- 2023
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Ingår i: New Journal of Physics. - 1367-2630. ; 25:12
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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