The research devised efficient methods for simulating 3-qubit Quantum Fourier Transform (QFT) circuits using Quick Quantum Circuit Simulation (QQCS). The hybrid methodologies suggested as a solution for efficiently simulating the circuit involve the combination of decision diagrams and property exploitation techniques. This paper incorporated two methods based on decision diagrams: the reordering trick and decision diagram approximations, template-based optimization, and linear reversible circuit synthesis for property exploitation. The proposed approaches significantly improved and optimized quantum algorithms and hardware by aiming to simulate quantum circuits accurately and quickly. Simulations using QQCS proved the effectiveness of these strategies, which were then compared to the original circuit. The results yielded valuable insights into enhancing simulation efficiency while upholding circuit accuracy.
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 $\ensuremath{\le}2$.
In a recent breakthrough, Bravyi, Gosset and Konig (BGK) [Science, 2018] proved that simulating constant depth quantum circuits takes classical circuits
Ω(logn) depth. In our paper, we first formalise their notion of simulation, which we call possibilistic simulation. Then, from well-known results, we deduce that their circuits can be simulated in depth
O(log2n). Separately, we construct explicit classical circuits that can simulate any depth-
d quantum circuit with Clifford and
t T-gates in depth
O(d+t). Our classical circuits use
{NOT, AND, OR} gates of fan-in
≤2.