68 research outputs found
symQV: Automated Symbolic Verification of Quantum Programs
We present symQV, a symbolic execution framework for writing and verifying
quantum computations in the quantum circuit model. symQV can automatically
verify that a quantum program complies with a first-order specification. We
formally introduce a symbolic quantum program model. This allows to encode the
verification problem in an SMT formula, which can then be checked with a
delta-complete decision procedure. We also propose an abstraction technique to
speed up the verification process. Experimental results show that the
abstraction improves symQV's scalability by an order of magnitude to quantum
programs with 24 qubits (a 2^24-dimensional state space).Comment: This is the extended version of a paper with the same title that
appeared at FM 2023. Tool available at doi.org/10.5281/zenodo.740032
Shaded Tangles for the Design and Verification of Quantum Programs (Extended Abstract)
We give a scheme for interpreting shaded tangles as quantum programs, with
the property that isotopic tangles yield equivalent programs. We analyze many
known quantum programs in this way -- including entanglement manipulation and
error correction -- and in each case present a fully-topological formal
verification, yielding in several cases substantial new insight into how the
program works. We also use our methods to identify several new or generalized
procedures.Comment: In Proceedings QPL 2017, arXiv:1802.0973
(Un)decidable Problems about Reachability of Quantum Systems
We study the reachability problem of a quantum system modelled by a quantum
automaton. The reachable sets are chosen to be boolean combinations of (closed)
subspaces of the state space of the quantum system. Four different reachability
properties are considered: eventually reachable, globally reachable, ultimately
forever reachable, and infinitely often reachable. The main result of this
paper is that all of the four reachability properties are undecidable in
general; however, the last three become decidable if the reachable sets are
boolean combinations without negation
Foundations of quantum programming
Progress in the techniques of quantum devices has made people widely believe that large-scale and functional quantum computers will be eventually built. By then, super-powered quantum computer will solve many problems affecting economic and social life that cannot be addressed by classical computing. However, our experiences with classical computing suggest that once quantum computers become available in the future, quantum software will play a key role in exploiting their power, and quantum software market will even be much larger than quantum hardware market. Unfortunately, today's software development techniques are not suited to quantum computers due to the essential differences between the nature of the classical world and that of the quantum world. To lay a solid foundation for tomorrow's quantum software industry, it is critically essential to pursue systematic research into quantum programming methodology and techniques. © 2010 Springer-Verlag
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