Abstract Based on the correspondence between circuit Laplacian and Schrodinger equations, recent investigations have shown that classical electric circuits can be used to simulate various topological physics and Schrödinger's equation. Furthermore, a series of quantum‐inspired information processing has been implemented by using classical electric circuit networks. In this review, the similarity between the circuit Laplacian and the lattice Hamiltonian is analyzed, with topological physics introduced based on classical circuits. Subsequently, reviews of the research progress in quantum‐inspired information processing based on the electric circuit are provided, including discussions of topological quantum computing with classical circuits, quantum walk based on classical circuits, quantum combinational logics based on classical circuits, electric‐circuit realization of fast quantum search, implementing unitary transforms and so on.
In a breakthrough work, Bravyi, Gosset, and K\"onig (BGK) [Science 362, 308 (2018)] unconditionally proved that constant-depth quantum circuits are more powerful than their classical counterparts. Their result is equivalent to saying that a particular family of constant-depth quantum circuits takes classical circuits at least $\mathrm{\ensuremath{\Omega}}(logn)$ depth to ``simulate,'' in a certain sense. In our paper, we formalize their sense of simulation, which we call ``possibilistic simulation'' or ``
p-simulation,'' and construct explicit classical circuits that can
p-simulate any depth-
d quantum circuit with Clifford and
tT-gates in depth
O(d+t). Our classical circuits use
NOT,AND,OR gates of fan-in $\ensuremath{\le}2$.
•Classical superconducting circuit simulators are powerful and available. •Include Josephson junction as basic element. •Provide efficient time-domain simulations of complex circuits. •May show effects otherwise attributed to quantum circuits.
•Circuits of coupled superconducting qubits are being developed for quantum computing (QC). •Entangled quantum theory incompatible with classical simulators. •Quantum model difficult to simulate on conventional computers for complex circuits already being tested. •Classical circuit simulations should provide the baseline to compare with quantum effects, but this is seldom done. •Coupled oscillators are delocalized even in classical limit.