Zobrazeno 1 - 10
of 183
pro vyhledávání: '"Calsamiglia, J."'
We investigate the ultimate precision limits for quantum phase estimation in terms of the coherence, $C$, of the probe. For pure states, we give the minimum estimation variance attainable, $V(C)$, and the optimal state, in the asymptotic limit when t
Externí odkaz:
http://arxiv.org/abs/2207.05656
Publikováno v:
Phys. Rev. Research 2, 033295 (2020)
The optimal discrimination of coherent states of light with current technology is a key problem in classical and quantum communication, whose solution would enable the realization of efficient receivers for long-distance communications in free-space
Externí odkaz:
http://arxiv.org/abs/2001.10283
We consider the problem of correctly identifying a malfunctioning quantum device that forms part of a network of $N$ such devices, which can be considered as the quantum analogue of classical anomaly detection. In the case where the devices in questi
Externí odkaz:
http://arxiv.org/abs/1808.02729
Publikováno v:
New J. Phys. 18 (2016) 103049
We show on theoretical grounds that, even in the presence of noise, probabilistic measurement strategies (which have a certain probability of failure or abstention) can provide, upon a heralded successful outcome, estimates with a precision that exce
Externí odkaz:
http://arxiv.org/abs/1610.08272
Quantum-enhanced measurements exploit quantum mechanical effects to provide ultra-precise estimates of physical variables for use in advanced technologies, such as frequency calibration of atomic clocks, gravitational waves detection, and biosensing.
Externí odkaz:
http://arxiv.org/abs/1407.6910
Publikováno v:
Phys. Rev. Lett. 113, 260402 (2014)
It has been recently shown that probabilistic protocols based on postselection boost the performances of phase estimation and the replication of quantum clocks. Here we demonstrate that the improvements in these two tasks have to match exactly in the
Externí odkaz:
http://arxiv.org/abs/1406.2218
Publikováno v:
Phys. Rev. A 88, 052304 (2013)
The problem of optimally discriminating between two completely unknown qubit states is generalized by allowing an error margin. It is visualized as a device---the programmable discriminator---with one data and two program ports, each fed with a numbe
Externí odkaz:
http://arxiv.org/abs/1308.1378
Publikováno v:
Phys. Rev. A 88, 012128 (2013)
The problems of optimally estimating a phase, a direction, and the orientation of a Cartesian frame (or trihedron) with general pure states are addressed. Special emphasis is put on estimation schemes that allow for inconclusive answers or abstention
Externí odkaz:
http://arxiv.org/abs/1306.4861
Publikováno v:
Phys. Rev. Lett. 110, 100501 (2013)
The main goal of quantum metrology is to obtain accurate values of physical parameters using quantum probes. In this context, we show that abstention, i.e., the possibility of getting an inconclusive answer at readout, can drastically improve the mea
Externí odkaz:
http://arxiv.org/abs/1209.5736
Publikováno v:
Sci. Rep. 2, 708 (2012)
A quantum learning machine for binary classification of qubit states that does not require quantum memory is introduced and shown to perform with the minimum error rate allowed by quantum mechanics for any size of the training set. This result is sho
Externí odkaz:
http://arxiv.org/abs/1208.0663