Using and reusing coherence to realize quantum processes
María García Díaz,Kun Fang,Xin Wang,Matteo Rosati,Michalis Skotiniotis,John Calsamiglia,Andreas Winter,Andreas Winter +7 more
- Vol. 2, pp 100
TLDR
It is found that in general a quantum channel can be implemented without employing a maximally coherent resource state, and it is proved that every pure coherent state in dimension larger than 2 turns out to be a valuable resource to implement some coherent unitary channel.Abstract:
Coherent superposition is a key feature of quantum mechanics that underlies the advantage of quantum technologies over their classical counterparts. Recently, coherence has been recast as a resource theory in an attempt to identify and quantify it in an operationally well-defined manner. Here we study how the coherence present in a state can be used to implement a quantum channel via incoherent operations and, in turn, to assess its degree of coherence. We introduce the robustness of coherence of a quantum channel---which reduces to the homonymous measure for states when computed on constant-output channels---and prove that: i) it quantifies the minimal rank of a maximally coherent state required to implement the channel; ii) its logarithm quantifies the amortized cost of implementing the channel provided some coherence is recovered at the output; iii) its logarithm also quantifies the zero-error asymptotic cost of implementation of many independent copies of a channel. We also consider the generalized problem of imperfect implementation with arbitrary resource states. Using the robustness of coherence, we find that in general a quantum channel can be implemented without employing a maximally coherent resource state. In fact, we prove that \textit{every} pure coherent state in dimension larger than $2$, however weakly so, turns out to be a valuable resource to implement \textit{some} coherent unitary channel. We illustrate our findings for the case of single-qubit unitary channels.read more
Citations
More filters
Proceedings Article
Quantum communication
Nicolas Gisin,Hugo Zbinden +1 more
TL;DR: World specialists will talk about reliability tests in quantum networks; about quantum hacking, its importance and limitations, and its role in classical and quantum cryptography; about high rate and about low cost QKD systems; about free space quantum communication; and about future quantum repeaters for continental scale quantum communication.
Journal ArticleDOI
Nonclassicality as a Quantifiable Resource for Quantum Metrology.
TL;DR: The Letter reveals that a single copy, highly non classical quantum state is intrinsically advantageous when compared to multiple copies of a quantum state with moderate nonclassicality, suggesting that metrological power is related to the degree of quantum macroscopicity.
Journal ArticleDOI
Operational resource theory of quantum channels
TL;DR: In this paper, the authors propose a general resource framework for quantum channels based on which they study general connections between channel and state resource theories and investigate general properties of the operational resource theory of channels, without specifying the resource being studied.
Journal ArticleDOI
Quantifying Operations with an Application to Coherence.
TL;DR: This work presents two measures quantifying the ability of an operation to detect, i.e., to use, coherence, one of them with an operational interpretation, and provides methods to evaluate them.
Journal ArticleDOI
General Resource Theories in Quantum Mechanics and Beyond: Operational Characterization via Discrimination Tasks
Ryuji Takagi,Bartosz Regula +1 more
TL;DR: This work finds that discrimination tasks provide a unified operational description for quantification and manipulation of resources by showing that the family of robustness measures can be understood as the maximum advantage provided by any physical resource in several different discrimination tasks, as well as establishing that such discrimination problems can fully characterize the allowed transformations within the given resource theory.
References
More filters
Journal ArticleDOI
Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?
TL;DR: Consideration of the problem of making predictions concerning a system on the basis of measurements made on another system that had previously interacted with it leads to the result that one is led to conclude that the description of reality as given by a wave function is not complete.
Journal ArticleDOI
Quantum entanglement
TL;DR: In this article, the basic aspects of entanglement including its characterization, detection, distillation, and quantification are discussed, and a basic role of entonglement in quantum communication within distant labs paradigm is discussed.
Journal ArticleDOI
Quantum Cryptography
TL;DR: The author revealed that quantum teleportation as “Quantum one-time-pad” had changed from a “classical teleportation” to an “optical amplification, privacy amplification and quantum secret growing” situation.
Journal ArticleDOI
A single quantum cannot be cloned
TL;DR: In this article, the linearity of quantum mechanics has been shown to prevent the replication of a photon of definite polarization in the presence of an excited atom, and the authors show that this conclusion holds for all quantum systems.
Journal ArticleDOI
Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems
Gregory S. Engel,Gregory S. Engel,Tessa R. Calhoun,Tessa R. Calhoun,Elizabeth L. Read,Elizabeth L. Read,Tae Kyu Ahn,Tae Kyu Ahn,Tomáš Mančal,Tomáš Mančal,Tomáš Mančal,Yuan-Chung Cheng,Yuan-Chung Cheng,Robert E. Blankenship,Graham R. Fleming,Graham R. Fleming +15 more
TL;DR: Previous two-dimensional electronic spectroscopy investigations of the FMO bacteriochlorophyll complex are extended, and direct evidence is obtained for remarkably long-lived electronic quantum coherence playing an important part in energy transfer processes within this system is obtained.