1. A Compact Noise-Tolerant Algorithm for Unbiased Quantum Simulation Using Feynman's $iη$ Prescription
- Author
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Lee, Woo-Ram, Scott, Ryan, and Scarola, V. W.
- Subjects
Strongly Correlated Electrons (cond-mat.str-el) ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
Quantum simulation advantage over classical memory limitations would allow compact quantum circuits to yield insight into intractable quantum many-body problems. But the interrelated obstacles of large circuit depth in quantum time evolution and noise seem to rule out unbiased quantum simulation in the near term. We prove that Feynman's $iη$ prescription exponentially improves the circuit depth needed for quantum time evolution. We apply the prescription to the construction of a hybrid quantum/classical algorithm to estimate a useful observable, energy gap. We prove the algorithm's tolerance to all common Markovian noise channels. We demonstrate the success of the algorithm within an operation window by using it to perform unbiased finite-size scaling of the transverse-field Ising model using an IBMQ device and related noise models. Our findings set the stage for unbiased quantum gap estimation without implementing quantum error-correcting codes on early fault-tolerant machines where non-Markovian noise is kept below tolerances., 12 pages, 11 figures, 1 table
- Published
- 2022
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