arXiv subjects

Andrey Zhukov

Publications and source records attributed to Andrey Zhukov.

2 recordsLinked to original sources

arXiv2026

Exact quantum circuits for a Heisenberg triangle with Dzyaloshinskii-Moriya interaction

We construct exact quantum circuits for a three-spin Heisenberg triangle with Dzyaloshinskii-Moriya (DM) interaction. A change of basis reduces pure DM evolution with arbitrary couplings to two single-qubit rotations, giving a circuit with at most 8 CNOT gates. When $J$ and $D$ are each the same on all bonds, one fixed basis gives a circuit with at most 10 CNOT gates for any real $J,D,t$. Local spin rotations extend the construction to a family with unequal DM couplings and nonzero exchange, requiring at most 14 CNOT gates. All circuits act on the full Hilbert space. An alternative pure DM implementation uses five two-qubit DM gates: analytically retuning the angles of one symmetric Strang step makes it exact. A 12-spin kagome example illustrates the use of these exact local blocks in lattice simulation.

quant-ph↗

arXiv2025

Grover's search meets Ising models: a quantum algorithm for finding low-energy states

We propose a methodology for implementing Grover's algorithm in the digital quantum simulation of disordered Ising models. The core concept revolves around using the evolution operator for the Ising model as the quantum oracle within Grover's search. This operator induces phase shifts for the eigenstates of the Ising Hamiltonian, with the most pronounced shifts occurring for the lowest and highest energy states. Determining these states for a disordered Ising Hamiltonian using classical methods presents an exponentially complex challenge with respect to the number of spins (or qubits) involved. Within our proposed approach, we determine the optimal evolution time by ensuring a phase flip for the target states. This method yields a quadratic speedup compared to classical computation methods and enables the identification of the lowest and highest energy states (or neighboring states) with a high probability $\lesssim 1$.

quant-ph↗