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Resource theories are broad frameworks that capture how useful objects are in performing specific tasks. In this paper we devise a formal resource theory quantum measurements, focusing on the ability of a measurement to acquire information.…

Quantum Physics · Physics 2021-05-03 Thomas Guff , Nathan A. McMahon , Yuval R. Sanders , Alexei Gilchrist

In this paper we shall introduce the mathematical framework for the description of measurements of quantum processes. Using this framework the process estimation problems can be treated in the similar way as the state estimation problems,…

Quantum Physics · Physics 2009-11-13 Mario Ziman

We propose a time-of-arrival operator in quantum mechanics by conditioning on a quantum clock. This allows us to bypass some of the problems of previous proposals, and to obtain a Hermitian time of arrival operator whose probability…

Quantum Physics · Physics 2020-03-19 Lorenzo Maccone , Krzysztof Sacha

In many a traditional physics textbook, a quantum measurement is defined as a projective measurement represented by a Hermitian operator. In quantum information theory, however, the concept of a measurement is dealt with in complete…

Quantum Physics · Physics 2015-11-06 Ravi Kunjwal , Chris Heunen , Tobias Fritz

Quantum coherence is a fundamental resource that quantum technologies exploit to achieve performance beyond that of classical devices. A necessary prerequisite to achieve this advantage is the ability of measurement devices to detect…

We study the construction of probability densities for time-of-arrival in quantum mechanics. Our treatment is based upon the facts that (i) time appears in quantum theory as an external parameter to the system, and (ii) propositions about…

Quantum Physics · Physics 2015-06-26 Charis Anastopoulos , Ntina Savvidou

Within quantum mechanics it is possible to assign a probability to the chance that a measurement has been made at a specific time t. However, the interpretation of such a probability is far from clear. We argue that a recent measuring…

Quantum Physics · Physics 2007-05-23 J. Oppenheim , B. Reznik , W. G. Unruh

We consider the general measurement scenario in which the ensemble average of an operator is determined via suitable data-processing of the outcomes of a quantum measurement described by a POVM. After reviewing the optimization of data…

Quantum Physics · Physics 2007-05-23 Paolo Perinotti , Giacomo M. D'Ariano

Quantum mechanics relates probability of an observable event to the absolute square of the corresponding probability amplitude. It may, therefore, seem that the information about the amplitudes' phases must be irretrievably lost in the…

Quantum Physics · Physics 2019-07-30 D. Sokolovski , S. Martínez-Garaot , M. Pons

We study the decay of unstable states by formulating quantum tunneling as a time-of-arrival problem: we determine the detection probability for particles at a detector located a distance L from the tunneling region. For this purpose, we use…

Quantum Physics · Physics 2009-11-13 Charis Anastopoulos

A generic unital positive operator-valued measure (POVM), which transforms a given stationary pure state to an arbitrary statistical state with perfect decoherence, is presented. This allows one to operationally realize thermalization as a…

Statistical Mechanics · Physics 2011-09-09 Sumiyoshi Abe , Yuichi Itto , Mamoru Matsunaga

Randomness is a central feature of quantum mechanics and an invaluable resource for both classical and quantum technologies. Commonly, in Device-Independent and Semi-Device-Independent scenarios, randomness is certified using projective…

Quantum Physics · Physics 2022-11-08 Marco Avesani , Hamid Tebyanian , Paolo Villoresi , Giuseppe Vallone

We introduce a single-number metric, quantum volume, that can be measured using a concrete protocol on near-term quantum computers of modest size ($n\lesssim 50$), and measure it on several state-of-the-art transmon devices, finding values…

Quantum Physics · Physics 2019-10-14 Andrew W. Cross , Lev S. Bishop , Sarah Sheldon , Paul D. Nation , Jay M. Gambetta

The spin-coherent-state positive-operator-valued-measure (POVM) is a fundamental measurement in quantum science, with applications including tomography, metrology, teleportation, benchmarking, and measurement of Husimi phase space…

Quantum Physics · Physics 2018-10-03 Ezad Shojaee , Christopher S. Jackson , Carlos A. Riofrio , Amir Kalev , Ivan H. Deutsch

The attempt to gain a theoretical understanding of the concept of time in quantum mechanics has triggered significant progress towards the search for faster and more efficient quantum technologies. One of such advances consists in the…

A paradigm shift in quantum thermometry is proposed. To date, thermometry has relied on local estimation, which is useful to reduce statistical fluctuations once the temperature is very well known. In order to estimate temperatures in cases…

Quantum Physics · Physics 2021-11-04 Jesús Rubio , Janet Anders , Luis A. Correa

It is commonly believed that the most general type of a quantum-mechanical measurement is one described by a positive-operator valued measure (POVM). In the present paper, this statement is proven for any measurements on quantum systems…

Quantum Physics · Physics 2014-02-13 A. V. Nenashev

Quantum tomography is the main method used to assess the quality of quantum information processing devices, but its complexity presents a major obstacle for the characterization of even moderately large systems. The number of experimental…

Quantum Physics · Physics 2015-03-19 Marcus P. da Silva , Olivier Landon-Cardinal , David Poulin

We consider the apparatus in a quantum measurement process to be in a mixed state. We propose a simple upper bound on the probability of correctly distinguishing any number of mixed states. We use this to derive fundamental bounds on the…

Quantum Physics · Physics 2007-05-23 S. Bose , V. Vedral

The traditional quantum speed limits are not attainable for many physical processes, as they tend to be loose and fail to determine the exact time taken by quantum systems to evolve. To address this, we derive exact quantum speed limits for…

Quantum Physics · Physics 2023-08-30 Arun K. Pati , Brij Mohan , Sahil , Samuel L. Braunstein