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An explicit algorithm for calculating the optimized Euler angles for both qubit state transfer and gate engineering given two arbitary fixed Hamiltonians is presented. It is shown how the algorithm enables us to efficiently implement single…

Quantum Physics · Physics 2009-12-03 K. Ch. Chatzisavvas , G. Chadzitaskos , C. Daskaloyannis , S. G. Schirmer

We consider the problem of strong (amplitude-wise) simulation of $n$-qubit quantum circuits, and identify a subclass of simulators we call monotone. This subclass encompasses almost all prominent simulation techniques. We prove an…

Quantum Physics · Physics 2018-05-02 Cupjin Huang , Michael Newman , Mario Szegedy

We derive an upper bound for the time needed to implement a generic unitary transformation in a $d$ dimensional quantum system using $d$ control fields. We show that given the ability to control the diagonal elements of the Hamiltonian,…

Quantum Physics · Physics 2020-04-22 Juneseo Lee , Christian Arenz , Daniel Burgarth , Herschel Rabitz

What interactions are sufficient to simulate arbitrary quantum dynamics in a composite quantum system? We provide an efficient algorithm to simulate any desired two-body Hamiltonian evolution using any fixed two-body entangling n-qubit…

Quantum Physics · Physics 2009-11-07 Jennifer L. Dodd , Michael A. Nielsen , Michael J. Bremner , Robert T. Thew

Let G(A,B) denote the 2-qubit gate which acts as the 1-qubit SU(2) gates A and B in the even and odd parity subspaces respectively, of two qubits. Using a Clifford algebra formalism we show that arbitrary uniform families of circuits of…

Quantum Physics · Physics 2008-11-19 Richard Jozsa , Akimasa Miyake

A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the…

Condensed Matter · Physics 2009-10-22 David P. Divincenzo

Experimental implementations of quantum computer architectures are now being investigated in many different physical settings. The full set of requirements that must be met to make quantum computing a reality in the laboratory [1] is…

Quantum Physics · Physics 2009-11-06 D. P. DiVincenzo , D. Bacon , J. Kempe , G. Burkard , K. B. Whaley

Today's devices for quantum computing are still far from implementing useful and powerful quantum algorithms. Decoherence and the wish to resist the effects of errors in a system of quantum bits incurs a lot of overhead in the number of…

Quantum Physics · Physics 2007-05-23 Torsten Asselmeyer-Maluga , Matthias Kolbe , Helge Rose'

Hamiltonian simulation is one of the most important problems in quantum computation, and quantum singular value transformation (QSVT) is an efficient way to simulate a general class of Hamiltonians. However, the QSVT circuit typically…

Quantum Physics · Physics 2023-05-15 Yulong Dong , K. Birgitta Whaley , Lin Lin

Digital quantum simulation has broad applications in approximating unitary evolution of Hamiltonians. In practice, many simulation tasks for quantum systems focus on quantum states in the low-energy subspace instead of the entire Hilbert…

Quantum Physics · Physics 2024-07-16 Weiyuan Gong , Shuo Zhou , Tongyang Li

The mapping of fermionic states onto qubit states, as well as the mapping of fermionic Hamiltonian into quantum gates enables us to simulate electronic systems with a quantum computer. Benefiting the understanding of many-body systems in…

Quantum Physics · Physics 2018-10-12 Mark Steudtner , Stephanie Wehner

In this paper, we study the optimal simulation of three-qubit unitary by using two-qubit gates. First, we give a lower bound on the two-qubit gates cost of simulating a multi-qubit gate. Secondly, we completely characterize the two-qubit…

Quantum Physics · Physics 2013-01-17 Nengkun Yu , Mingsheng Ying

We investigate Clifford+$T$ quantum circuits with a small number of $T$-gates. Using the sparsification lemma, we identify time complexity lower bounds in terms of $T$-gate count below which a strong simulator would improve on the…

Quantum Physics · Physics 2019-02-26 Cupjin Huang , Michael Newman , Mario Szegedy

Near-term quantum computers are limited by the decoherence of qubits to only being able to run low-depth quantum circuits with acceptable fidelity. This severely restricts what quantum algorithms can be compiled and implemented on such…

We numerically analyze the feasibility of a platform-neutral, general strategy to perform quantum simulations of fermionic lattice field theories under open boundary conditions. The digital quantum simulator requires solely one- and…

Quantum computation and quantum control operate by building unitary transformations out of sequences of elementary quantum logic operations or applications of control fields. This paper puts upper bounds on the minimum time required to…

Quantum Physics · Physics 2019-01-14 Seth Lloyd , Reevu Maity

We investigate the time T a quantum computer requires to factorize a given number dependent on the number of bits L required to represent this number. We stress the fact that in most cases one has to take into account that the execution…

Quantum Physics · Physics 2009-10-28 M. B. Plenio , P. L. Knight

Quantum chemistry simulations on a quantum computer suffer from the overhead needed for encoding the fermionic problem in a bosonic system of qubits. By exploiting the block diagonality of a fermionic Hamiltonian, we show that the number of…

Quantum Physics · Physics 2016-06-09 Nikolaj Moll , Andreas Fuhrer , Peter Staar , Ivano Tavernelli

We study the computation power of lattices composed of two dimensional systems (qubits) on which translationally invariant global two-qubit gates can be performed. We show that if a specific set of 6 global two qubit gates can be performed,…

Quantum Physics · Physics 2014-03-06 G. Ivanyos , S. Massar , A. B. Nagy

We propose a new implementation of a universal set of one- and two-qubit gates for quantum computation using the spin states of coupled single-electron quantum dots. Desired operations are effected by the gating of the tunneling barrier…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Daniel Loss , David P. DiVincenzo