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QML Journal Club
Speaker: Kishor Bharti, CQT
Time: Feb 25, 10: 00 AM
Title: A blueprint for practical quantum advantage
Abstract:
We are in the regime of noisy intermediate-scale quantum (NISQ) devices. The "quantum supremacy" experiments by the Google team and Jian-Wei Pan's group have demonstrated such devices' power for computationally contrived examples. So far, a practical quantum advantage is missing. Our best hope has been variational quantum algorithms in the search for quantum advantage, particularly variational quantum eigensolver (VQE) and variational quantum simulator (VQS). These algorithms employ a classical-quantum feedback loop to update the parameters of a parametric quantum circuit (PQC). However, these algorithms have many limitations related to trainability (the barren plateau problem) and expressibility. There is no systematic way to construct a problem-aware Ansatz which can be efficiently implemented on the existing hardware.

In this talk, I will discuss a new generation of algorithms alternative to VQE and VQS. As a systematic alternative to VQE, I will discuss quantum assisted eigensolver (QAE), and iterative quantum assisted eigensolver (IQAE). As a substitute for VQS, I will discuss quantum assisted simulator (QAS). These algorithms (QAE, IQAE and QAS) do not require any classical-quantum feedback loop and can be executed exceptionally faster than VQE and VQS. These algorithms render a systematic approach to construct ansatz, circumvent the barren plateau problem, and not require any complicated controlled multi-qubit unitaries, as in VQS. Our algorithms can be implemented immediately on the current-term hardware and thus provide the hope for quantum advantage in the NISQ era.

Feb 25, 2021 10:00 AM in Singapore

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