2,067 research outputs found
Quantum-enhanced Secure Delegated Classical Computing
We present a quantumly-enhanced protocol to achieve unconditionally secure
delegated classical computation where the client and the server have both
limited classical and quantum computing capacity. We prove the same task cannot
be achieved using only classical protocols. This extends the work of Anders and
Browne on the computational power of correlations to a security setting.
Concretely, we present how a client with access to a non-universal classical
gate such as a parity gate could achieve unconditionally secure delegated
universal classical computation by exploiting minimal quantum gadgets. In
particular, unlike the universal blind quantum computing protocols, the
restriction of the task to classical computing removes the need for a full
universal quantum machine on the side of the server and makes these new
protocols readily implementable with the currently available quantum technology
in the lab
Quantum-enhanced Secure Delegated Classical Computing
International audienc
Energy efficient mining on a quantum-enabled blockchain using light
We outline a quantum-enabled blockchain architecture based on a consortium of
quantum servers. The network is hybridised, utilising digital systems for
sharing and processing classical information combined with a fibre--optic
infrastructure and quantum devices for transmitting and processing quantum
information. We deliver an energy efficient interactive mining protocol enacted
between clients and servers which uses quantum information encoded in light and
removes the need for trust in network infrastructure. Instead, clients on the
network need only trust the transparent network code, and that their devices
adhere to the rules of quantum physics. To demonstrate the energy efficiency of
the mining protocol, we elaborate upon the results of two previous experiments
(one performed over 1km of optical fibre) as applied to this work. Finally, we
address some key vulnerabilities, explore open questions, and observe
forward--compatibility with the quantum internet and quantum computing
technologies.Comment: 25 pages, 5 figure
Towards a Unified Quantum Protocol Framework: Classification, Implementation, and Use Cases
We present a framework for the unification and standardization of quantum
network protocols, making their realization easier and expanding their use
cases to a broader range of communities interested in quantum technologies. Our
framework is available as an open-source repository, the Quantum Protocol Zoo.
We follow a modular approach by identifying two key components: Functionality,
which connects real-world applications; and Protocol, which is a set of
instructions between two or many parties, at least one of which has a quantum
device. Based on the different stages of the quantum internet and use-case in
the commercialization of quantum communication, our framework classifies
quantum cryptographic functionalities and the various protocol designs
implementing these functionalities. Towards this classification, we introduce a
novel concept of resource visualization for quantum protocols, which includes
two interfaces: one to identify the building blocks for implementing a given
protocol and another to identify accessible protocols when certain physical
resources or functionalities are available. Such classification provides a
hierarchy of quantum protocols based on their use-case and resource allocation.
We have identified various valuable tools to improve its representation with a
range of techniques, from abstract cryptography to graphical visualizations of
the resource hierarchy in quantum networks. We elucidate the structure of the
zoo and its primary features in this article to a broader class of quantum
information scientists, physicists, computer science theorists and end-users.
Since its introduction in 2018, the quantum protocol zoo has been a cornerstone
in serving the quantum networks community in its ability to establish the use
cases of emerging quantum internet networks. In that spirit we also provide
some of the applications of our framework from different perspectives.Comment: 12 pages, 6 figure
Complexity-Theoretic Limitations on Blind Delegated Quantum Computation
Blind delegation protocols allow a client to delegate a computation to a
server so that the server learns nothing about the input to the computation
apart from its size. For the specific case of quantum computation we know that
blind delegation protocols can achieve information-theoretic security. In this
paper we prove, provided certain complexity-theoretic conjectures are true,
that the power of information-theoretically secure blind delegation protocols
for quantum computation (ITS-BQC protocols) is in a number of ways constrained.
In the first part of our paper we provide some indication that ITS-BQC
protocols for delegating computations in which the client and the
server interact only classically are unlikely to exist. We first show that
having such a protocol with bits of classical communication implies
that . We conjecture that this
containment is unlikely by providing an oracle relative to which . We then show that if an ITS-BQC protocol
exists with polynomial classical communication and which allows the client to
delegate quantum sampling problems, then there exist non-uniform circuits of
size , making polynomially-sized queries to
an oracle, for computing the permanent of an matrix.
The second part of our paper concerns ITS-BQC protocols in which the client and
the server engage in one round of quantum communication and then exchange
polynomially many classical messages. First, we provide a complexity-theoretic
upper bound on the types of functions that could be delegated in such a
protocol, namely . Then, we show that
having such a protocol for delegating -hard functions implies
.Comment: Improves upon, supersedes and corrects our earlier submission, which
previously included an error in one of the main theorem
Machines, Logic and Quantum Physics
Though the truths of logic and pure mathematics are objective and independent
of any contingent facts or laws of nature, our knowledge of these truths
depends entirely on our knowledge of the laws of physics. Recent progress in
the quantum theory of computation has provided practical instances of this, and
forces us to abandon the classical view that computation, and hence
mathematical proof, are purely logical notions independent of that of
computation as a physical process. Henceforward, a proof must be regarded not
as an abstract object or process but as a physical process, a species of
computation, whose scope and reliability depend on our knowledge of the physics
of the computer concerned.Comment: 19 pages, 8 figure
Probabilistic one-time programs using quantum entanglement
It is well known that quantum technology allows for an unprecedented level of
data and software protection for quantum computers as well as for
quantum-assisted classical computers. To exploit these properties,
probabilistic one-time programs have been developed, where the encoding of
classical software in small quantum states enables computer programs that can
be used only once. Such self-destructing one-time programs facilitate a variety
of new applications reaching from software distribution to one-time delegation
of signature authority. Whereas first proof-of-principle experiments
demonstrated the feasibility of such schemes, the practical applications were
limited due to the requirement of using the software on-the-fly combined with
technological challenges due to the need for active optical switching and a
large amount of classical communication. Here we present an improved protocol
for one-time programs that resolves major drawbacks of previous schemes, by
employing entangled qubit pairs. This results in four orders of magnitude
higher count rates as well the ability to execute a program long after the
quantum information exchange has taken place. We demonstrate our protocol over
an underground fiber link between university buildings in downtown Vienna.
Finally, together with our implementation of a one-time delegation of signature
authority this emphasizes the compatibility of our scheme with
prepare-and-measure quantum internet networks
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