Archivio istituzionale della ricerca della Scuola Normale Superiore
IRIS SNS è l'archivio istituzionale destinato a raccogliere, conservare e diffondere ad accesso aperto la produzione scientifica degli autori afferenti alla Scuola Normale Superiore.
EnglishWe search for the optimal quantum pure states of identical bosonic particles for applications in quantum metrology, in particular in the estimation of a single parameter for the generic two-mode interferometric setup. We consider the general case in which the total number of particles is fluctuating around an average $N$ with variance $\Delta N^2$. By recasting the problem in the framework of classical probability, we clarify the maximal accuracy attainable and show that it is always larger than the one reachable with a fixed number of particles (i.e., $\Delta N=0$). In particular, for larger fluctuations, the error in the estimation diminishes proportionally to $1/\Delta N$, below the Heisenberg-like scaling $1/N$. We also clarify the best input state, which is a "quasi-NOON state" for a generic setup, and for some special cases a two-mode "Schr\"odinger-cat state" with a vacuum component. In addition, we search for the best state within the class of pure Gaussian states with a given average $N$, which is revealed to be a product state (with no entanglement) with a squeezed vacuum in one mode and the vacuum in the other.
| Titolo: | Two-mode bosonic quantum metrology with number fluctuations | |
| Autori: | ||
| Data di pubblicazione: | 2015 | |
| Rivista: | ||
| Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevA.92.042115 | |
| Parole Chiave: | Quantum Physics; Quantum Physics; Mathematical Physics; Mathematics - Mathematical Physics | |
| Handle: | http://hdl.handle.net/11384/60291 | |
| Appare nelle tipologie: | 1.1 Articolo in rivista |
File in questo prodotto:
http://hdl.handle.net/11384/60291
Copyright © 2022