Teleportation costs analyzed for distributed quantum chemistry calculations
Quantifying Teleportation Overhead in Distributed Unitary Coupled-Cluster Ansätze
Distributed, Parallel, and Cluster Computing
Summary
Running quantum chemistry calculations on multiple quantum computers working together is tricky because some steps need special communication called teleportation. The authors looked at different ways to set up these calculations and measured how much teleportation is needed. They found that some methods use fewer resources, making them easier to run on distributed quantum systems. This helps understand how to do these calculations more efficiently across multiple quantum machines.
What this means in practice
- •For quantum algorithm developers: Estimate and minimize teleportation overhead in distributed quantum algorithms for chemistry simulations.
- •For quantum hardware teams: Design communication protocols to handle nonlocal quantum gates efficiently in modular quantum processors.
Authors
Grier M. Jones, Hassan Tariq Shafi, Zixuan Wang, Thomas Trenty, Zachary Vernec, Hans-Arno Jacobsen
Abstract
Distributed quantum computing (DQC) has been proposed as a way to scale quantum algorithms for practical applications beyond monolithic quantum processor architectures. Among these applications, quantum chemistry is widely regarded as one of the most promising use cases for quantum computing. In this work, we estimate the distributed-resource requirements of unitary coupled-cluster (UCC) ansätze for quantum chemistry, focusing on unitary coupled-cluster singles and doubles (UCCSD), unitary pair coupled-cluster doubles (UpCCD), and unitary pair coupled-cluster with generalized singles and doubles (UpCCGSD) circuits for hydrogen chains. We focus on a teleportation-based approach to DQC, quantitatively comparing a naive distribution method to the output of the TeleSABRE algorithm. For both approaches, we estimate the cost of handling nonlocal two-qubit gates across a fixed midpoint or quarter-point partition, reporting Bell-pair/classical-communication costs in teleportation. Across Jordan-Wigner and Bravyi-Kitaev, we find that UpCCD with spin-blocked Jordan-Wigner ordering gives the most favorable scaling, while UCCSD incurs substantially larger distributed-resource requirements.