1,720,960 research outputs found
Self-testing of a single quantum device under computational assumptions
Get PDFSelf-testing is a method to characterise an arbitrary quantum system based
only on its classical input-output correlations, and plays an important role in
device-independent quantum information processing as well as quantum complexity
theory. Prior works on self-testing require the assumption that the system's
state is shared among multiple parties that only perform local measurements and
cannot communicate. Here, we replace the setting of multiple non-communicating
parties, which is difficult to enforce in practice, by a single computationally
bounded party. Specifically, we construct a protocol that allows a classical
verifier to robustly certify that a single computationally bounded quantum
device must have prepared a Bell pair and performed single-qubit measurements
on it, up to a change of basis applied to both the device's state and
measurements. This means that under computational assumptions, the verifier is
able to certify the presence of entanglement, a property usually closely
associated with two separated subsystems, inside a single quantum device. To
achieve this, we build on techniques first introduced by Brakerski et al.
(2018) and Mahadev (2018) which allow a classical verifier to constrain the
actions of a quantum device assuming the device does not break post-quantum
cryptography.Comment: 58 pages, published in Quantu
Concentration bounds for quantum states and limitations on the QAOA from polynomial approximations
Get PDFWe prove concentration bounds for the following classes of quantum states:
(i) output states of shallow quantum circuits, answering an open question from
[DPMRF22]; (ii) injective matrix product states; (iii) output states of dense
Hamiltonian evolution, i.e. states of the form for any -qubit product state
, where each can be any local commuting Hamiltonian
satisfying a norm constraint, including dense Hamiltonians with interactions
between any qubits. Our proofs use polynomial approximations to show that these
states are close to local operators. This implies that the distribution of the
Hamming weight of a computational basis measurement (and of other related
observables) concentrates.
An example of (iii) are the states produced by the quantum approximate
optimisation algorithm (QAOA). Using our concentration results for these
states, we show that for a random spin model, the QAOA can only succeed with
negligible probability even at super-constant level ,
assuming a strengthened version of the so-called overlap gap property. This
gives the first limitations on the QAOA on dense instances at super-constant
level, improving upon the recent result [BGMZ22].Comment: 28 pages. Extended abstract in ITCS 2023, full version (v3) in
Quantu
Quantum cryptography with classical communication: parallel remote state preparation for copy-protection, verification, and more
Get PDFQuantum mechanical effects have enabled the construction of cryptographic
primitives that are impossible classically. For example, quantum
copy-protection allows for a program to be encoded in a quantum state in such a
way that the program can be evaluated, but not copied. Many of these
cryptographic primitives are two-party protocols, where one party, Bob, has
full quantum computational capabilities, and the other party, Alice, is only
required to send random BB84 states to Bob. In this work, we show how such
protocols can generically be converted to ones where Alice is fully classical,
assuming that Bob cannot efficiently solve the LWE problem. In particular, this
means that all communication between (classical) Alice and (quantum) Bob is
classical, yet they can still make use of cryptographic primitives that would
be impossible if both parties were classical. We apply this conversion
procedure to obtain quantum cryptographic protocols with classical
communication for unclonable encryption, copy-protection, computing on
encrypted data, and verifiable blind delegated computation. The key technical
ingredient for our result is a protocol for classically-instructed parallel
remote state preparation of BB84 states. This is a multi-round protocol between
(classical) Alice and (quantum polynomial-time) Bob that allows Alice to
certify that Bob must have prepared uniformly random BB84 states (up to a
change of basis on his space). Furthermore, Alice knows which specific BB84
states Bob has prepared, while Bob himself does not. Hence, the situation at
the end of this protocol is (almost) equivalent to one where Alice sent
random BB84 states to Bob. This allows us to replace the step of preparing and
sending BB84 states in existing protocols by our remote-state preparation
protocol in a generic and modular way.Comment: 80 pages, 7 protocol
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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