4 research outputs found
Learning-based quantum error mitigation
If NISQ-era quantum computers are to perform useful tasks, they will need to
employ powerful error mitigation techniques. Quasi-probability methods can
permit perfect error compensation at the cost of additional circuit executions,
provided that the nature of the error model is fully understood and
sufficiently local both spatially and temporally. Unfortunately these
conditions are challenging to satisfy. Here we present a method by which the
proper compensation strategy can instead be learned ab initio. Our training
process uses multiple variants of the primary circuit where all non-Clifford
gates are substituted with gates that are efficient to simulate classically.
The process yields a configuration that is near-optimal versus noise in the
real system with its non-Clifford gate set. Having presented a range of
learning strategies, we demonstrate the power of the technique both with real
quantum hardware (IBM devices) and exactly-emulated imperfect quantum
computers. The systems suffer a range of noise severities and types, including
spatially and temporally correlated variants. In all cases the protocol
successfully adapts to the noise and mitigates it to a high degree.Comment: 28 pages, 19 figure
Error statistics and scalability of quantum error mitigation formulas
Quantum computing promises advantages over classical computing in many
problems. Nevertheless, noise in quantum devices prevents most quantum
algorithms from achieving the quantum advantage. Quantum error mitigation
provides a variety of protocols to handle such noise using minimal qubit
resources . While some of those protocols have been implemented in experiments
for a few qubits, it remains unclear whether error mitigation will be effective
in quantum circuits with tens to hundreds of qubits. In this paper, we apply
statistics principles to quantum error mitigation and analyse the scaling
behaviour of its intrinsic error. We find that the error increases linearly
with the gate number before mitigation and sub-linearly
after mitigation, where ,
is the error rate of a quantum gate, and is a
protocol-dependent factor. The scaling is a consequence of the law
of large numbers, and it indicates that error mitigation can suppress the error
by a larger factor in larger circuits. We propose the importance Clifford
sampling as a key technique for error mitigation in large circuits to obtain
this result
Evolocumab loaded Bio-Liposomes for efficient atherosclerosis therapy
Abstract PCSK9, which is closely related to atherosclerosis, is significantly expressed in vascular smooth muscle cells (VSMCs). Moreover, Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) mediated phenotypic transformation, abnormal proliferation, and migration of VSMCs play key roles in accelerating atherosclerosis. In this study, by utilizing the significant advantages of nano-materials, a biomimetic nanoliposome loading with Evolocumab (Evol), a PCSK9 inhibitor, was designed to alleviate atherosclerosis. In vitro results showed that (Lipo + M)@E NPs up-regulated the levels of α-SMA and Vimentin, while inhibiting the expression of OPN, which finally result in the inhibition of the phenotypic transition, excessive proliferation, and migration of VSMCs. In addition, the long circulation, excellent targeting, and accumulation performance of (Lipo + M)@E NPs significantly decreased the expression of PCSK9 in serum and VSMCs within the plaque of ApoE−/− mice