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Analog models of quantum information processing, such as adiabatic quantum computation and analog quantum simulation, require the ability to subject a system to precisely specified Hamiltonians. Unfortunately, the hardware used to implement…

Quantum Physics · Physics 2014-02-25 Kevin C. Young , Robin Blume-Kohout , Daniel A. Lidar

We present the results of a detailed analysis of a general, unstructured adiabatic quantum search of a data base of $N$ items. In particular we examine the effects on the computation time of adding energy to the system. We find that by…

Quantum Physics · Physics 2009-11-07 Saurya Das , Randy Kobes , Gabor Kunstatter

In the conventional quantum mechanics (i.e., hermitian QM) the adia- batic theorem for systems subjected to time periodic fields holds only for bound systems and not for open ones (where ionization and dissociation take place) [D. W. Hone,…

Atomic Physics · Physics 2009-11-11 Avner Fleischer , Nimrod Moiseyev

We propose an adiabatic quantum algorithm for generating a quantum pure state encoding of the PageRank vector, the most widely used tool in ranking the relative importance of internet pages. We present extensive numerical simulations which…

Quantum Physics · Physics 2012-06-05 Silvano Garnerone , Paolo Zanardi , Daniel A. Lidar

In the context of adiabatic quantum computation (AQC), it has been argued that first-order quantum phase transitions (QPTs) due to localisation phenomena cause AQC to fail by exponentially decreasing the minimal spectral gap of the…

Quantum Physics · Physics 2024-09-23 Matthias Werner , Artur García-Sáez , Marta P. Estarellas

We assess the prospects for algorithms within the general framework of quantum annealing (QA) to achieve a quantum speedup relative to classical state of the art methods in combinatorial optimization and related sampling tasks. We argue for…

Quantum Physics · Physics 2021-06-22 E. J. Crosson , D. A. Lidar

We systematically investigate quantum algorithms and lower bounds for mean estimation given query access to non-identically distributed samples. On the one hand, we give quantum mean estimators with quadratic quantum speed-up given samples…

Quantum Physics · Physics 2024-05-22 Jiachen Hu , Tongyang Li , Xinzhao Wang , Yecheng Xue , Chenyi Zhang , Han Zhong

We use the dynamical algebra of a quantum system and its dynamical invariants to inverse engineer feasible Hamiltonians for implementing shortcuts to adiabaticity. These are speeded up processes that end up with the same populations than…

Quantum Physics · Physics 2015-06-18 E. Torrontegui , S. Martínez-Garaot , J. G. Muga

Quantum adiabatic optimization (QAO) is performed using a time-dependent Hamiltonian $H(s)$ with spectral gap $\gamma(s)$. Assuming the existence of an oracle $\Gamma$ such that $\gamma_\min = \Theta\left(\min_s\Gamma(s)\right)$, we provide…

Quantum Physics · Physics 2019-04-19 Michael Jarret , Brad Lackey , Aike Liu , Kianna Wan

In a quantum system with a smoothly and slowly varying Hamiltonian, which approaches a constant operator at times $t\to \pm \infty$, the transition probabilities between adiabatic states are exponentially small. They are characterized by an…

Quantum Physics · Physics 2009-10-31 Michael Wilkinson , Michael A. Morgan

Quantum annealing is a continuous-time heuristic quantum algorithm for solving or approximately solving classical optimization problems. The algorithm uses a schedule to interpolate between a driver Hamiltonian with an easy-to-prepare…

Gate-based quantum computers can in principle simulate the adiabatic dynamics of a large class of Hamiltonians. Here we consider the cyclic adiabatic evolution of a parameter in the Hamiltonian. We propose a quantum algorithm to estimate…

Quantum Physics · Physics 2020-02-19 Bruno Murta , G. Catarina , J. Fernandez-Rossier

The computational cost of quantum algorithms for physics and chemistry is closely linked to the spectrum of the Hamiltonian, a property that manifests in the necessary rescaling of its eigenvalues. The typical approach of using the 1-norm…

We generalize the standard quantum adiabatic approximation to the case of open quantum systems. We define the adiabatic limit of an open quantum system as the regime in which its dynamical superoperator can be decomposed in terms of…

Quantum Physics · Physics 2007-05-23 M. S. Sarandy , D. A. Lidar

Understanding how non-adiabatic terms affect quantum dynamics is fundamental to improving various protocols for quantum technologies. We present a novel approach to computing the Adiabatic Gauge Potential (AGP), which gives information on…

Quantum Physics · Physics 2025-01-15 Ewen D C Lawrence , Sebastian F J Schmid , Ieva Čepaitė , Peter Kirton , Callum W Duncan

We develop a non-adiabatic generalization of holonomic quantum computation in which high-speed universal quantum gates can be realized by using non-Abelian geometric phases. We show how a set of non-adiabatic holonomic one- and two-qubit…

We develop further the approach to upper and lower bounds in quantum dynamics via complex analysis methods which was introduced by us in a sequence of earlier papers. Here we derive upper bounds for non-time averaged outside probabilities…

Spectral Theory · Mathematics 2014-12-30 David Damanik , Serguei Tcheremchantsev

Adiabatic quantum computing (AQC) started as an approach to solving optimization problems, and has evolved into an important universal alternative to the standard circuit model of quantum computing, with deep connections to both classical…

Quantum Physics · Physics 2018-02-05 Tameem Albash , Daniel A. Lidar

Adiabatic processes driven by non-Hermitian, time-dependent Hamiltonians may be sped up by generalizing inverse engineering techniques based on Berry's transitionless driving algorithm or on dynamical invariants. We work out the basic…

Quantum Physics · Physics 2015-09-18 S. Ibáñez , S. Martínez-Garaot , Xi Chen , E. Torrontegui , J. G. Muga

Adiabatic quantum computation has recently attracted attention in the physics and computer science communities, but its computational power was unknown. We describe an efficient adiabatic simulation of any given quantum algorithm, which…

Quantum Physics · Physics 2007-11-22 Dorit Aharonov , Wim van Dam , Julia Kempe , Zeph Landau , Seth Lloyd , Oded Regev