22 research outputs found
SQUARE: Strategic Quantum Ancilla Reuse for Modular Quantum Programs via Cost-Effective Uncomputation
Compiling high-level quantum programs to machines that are size constrained
(i.e. limited number of quantum bits) and time constrained (i.e. limited number
of quantum operations) is challenging. In this paper, we present SQUARE
(Strategic QUantum Ancilla REuse), a compilation infrastructure that tackles
allocation and reclamation of scratch qubits (called ancilla) in modular
quantum programs. At its core, SQUARE strategically performs uncomputation to
create opportunities for qubit reuse.
Current Noisy Intermediate-Scale Quantum (NISQ) computers and forward-looking
Fault-Tolerant (FT) quantum computers have fundamentally different constraints
such as data locality, instruction parallelism, and communication overhead. Our
heuristic-based ancilla-reuse algorithm balances these considerations and fits
computations into resource-constrained NISQ or FT quantum machines, throttling
parallelism when necessary. To precisely capture the workload of a program, we
propose an improved metric, the "active quantum volume," and use this metric to
evaluate the effectiveness of our algorithm. Our results show that SQUARE
improves the average success rate of NISQ applications by 1.47X. Surprisingly,
the additional gates for uncomputation create ancilla with better locality, and
result in substantially fewer swap gates and less gate noise overall. SQUARE
also achieves an average reduction of 1.5X (and up to 9.6X) in active quantum
volume for FT machines.Comment: 14 pages, 10 figure
Reqomp: Space-constrained Uncomputation for Quantum Circuits
Quantum circuits must run on quantum computers with tight limits on qubit and gate counts. To generate circuits respecting both limits, a promising opportunity is exploiting to trade qubits for gates. We present Reqomp, a method to automatically synthesize correct and efficient uncomputation of ancillae while respecting hardware constraints. For a given circuit, Reqomp can offer a wide range of trade-offs between tightly constraining qubit count or gate count. Our evaluation demonstrates that Reqomp can significantly reduce the number of required ancilla qubits by up to 96%. On 80% of our benchmarks, the ancilla qubits required can be reduced by at least 25% while never incurring a gate count increase beyond 28%
A Deductive Verification Framework for Circuit-building Quantum Programs
While recent progress in quantum hardware open the door for significant
speedup in certain key areas, quantum algorithms are still hard to implement
right, and the validation of such quantum programs is a challenge. Early
attempts either suffer from the lack of automation or parametrized reasoning,
or target high-level abstract algorithm description languages far from the
current de facto consensus of circuit-building quantum programming languages.
As a consequence, no significant quantum algorithm implementation has been
currently verified in a scale-invariant manner. We propose Qbricks, the first
formal verification environment for circuit-building quantum programs,
featuring clear separation between code and proof, parametric specifications
and proofs, high degree of proof automation and allowing to encode quantum
programs in a natural way, i.e. close to textbook style. Qbricks builds on best
practice of formal verification for the classical case and tailor them to the
quantum case: we bring a new domain-specific circuit-building language for
quantum programs, namely Qbricks-DSL, together with a new logical specification
language Qbricks-Spec and a dedicated Hoare-style deductive verification rule
named Hybrid Quantum Hoare Logic. Especially, we introduce and intensively
build upon HOPS, a higher-order extension of the recent path-sum symbolic
representation, used for both specification and automation. To illustrate the
opportunity of Qbricks, we implement the first verified parametric
implementations of several famous and non-trivial quantum algorithms, including
the quantum part of Shor integer factoring (Order Finding - Shor-OF), quantum
phase estimation (QPE) - a basic building block of many quantum algorithms, and
Grover search. These breakthroughs were amply facilitated by the specification
and automated deduction principles introduced within Qbricks
Dagstuhl News January - December 2011
"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic
LIPIcs, Volume 261, ICALP 2023, Complete Volume
LIPIcs, Volume 261, ICALP 2023, Complete Volum
Programming Languages and Systems
This open access book constitutes the proceedings of the 30th European Symposium on Programming, ESOP 2021, which was held during March 27 until April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The 24 papers included in this volume were carefully reviewed and selected from 79 submissions. They deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems