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In optimal quantum-mechanical evolutions, motion can occur along non-predetermined paths of shortest length in an optimal time. Alternatively, optimal evolutions can happen along predefined paths with no waste of energy resources and 100%…

Quantum Physics · Physics 2025-02-27 Leonardo Rossetti , Carlo Cafaro , Paul M. Alsing

Geometric effects make evolution time vary for different evolution curves that connect the same two quantum states. Thus, it is important to be able to control along which path a quantum state evolve to achieve maximal speed in quantum…

Quantum Physics · Physics 2013-05-01 Ole Andersson , Hoshang Heydari

In optimal quantum-mechanical evolutions, motion can take place along paths of minimal length within an optimal time frame. Alternatively, optimal evolutions may occur along established paths without any waste of energy resources and…

Quantum Physics · Physics 2026-01-16 Carlo Cafaro , James Schneeloch

Determining the quantum circuit complexity of a unitary operation is closely related to the problem of finding minimal length paths in a particular curved geometry [Nielsen et al, Science 311, 1133-1135 (2006)]. This paper investigates many…

Quantum Physics · Physics 2007-05-23 Mark R. Dowling , Michael A. Nielsen

It is known that mixed quantum states are highly entropic states of imperfect knowledge (i.e., incomplete information) about a quantum system, while pure quantum states are states of perfect knowledge (i.e., complete information) with…

Quantum Physics · Physics 2022-11-23 Carlo Cafaro , Paul M. Alsing

A unitary evolution in time may be treated as a curve in the manifold of the special unitary group. The length of such a curve can be related to the energetic cost of the associated computation, meaning a geodesic curve identifies an…

We study the complexity of both time-optimal and time sub-optimal quantum Hamiltonian evolutions connecting arbitrary source and a target states on the Bloch sphere equipped with the Fubini-Study metric. This investigation is performed in a…

Quantum Physics · Physics 2024-11-28 Carlo Cafaro , Leonardo Rossetti , Paul M. Alsing

We present an information geometric analysis of entropic speeds and entropy production rates in geodesic evolution on manifolds of parametrized quantum states. These pure states emerge as outputs of suitable su(2; C) time-dependent…

Quantum Physics · Physics 2020-02-26 Carlo Cafaro , Paul M. Alsing

In the geometry of quantum-mechanical processes, the time-varying curvature coefficient of a quantum evolution is specified by the magnitude squared of the covariant derivative of the tangent vector to the state vector. In particular, the…

Quantum Physics · Physics 2025-01-07 Carlo Cafaro , Leonardo Rossetti , Paul M. Alsing

We investigate the optimization of quantum control from a differential geometric perspective. In our approach, optimal control minimizes the cost associated with evolving a quantum state, with the cost quantified by the length of the…

Quantum Physics · Physics 2025-05-27 Chengming Tan , Yuhao Cai , Jinyi Zhang , Shengli Ma , Chenwei Lv , Ren Zhang

We present a comparative analysis of two different constructions of optimal-speed quantum Hamiltonian evolutions on the Bloch sphere. In the first approach (Mostafazadeh's approach), the evolution is specified by a traceless stationary…

Quantum Physics · Physics 2024-08-23 Leonardo Rossetti , Carlo Cafaro , Newshaw Bahreyni

We elucidate the geometry of quantum adiabatic evolution. By minimizing the deviation from adiabaticity we find a Riemannian metric tensor underlying adiabatic evolution. Equipped with this tensor, we identify a unified geometric…

Quantum Physics · Physics 2010-10-28 Ali T. Rezakhani , Damian F. Abasto , Daniel A. Lidar , Paolo Zanardi

We use geometric concepts originally proposed by Anandan and Aharonov to show that the Farhi-Gutmann time optimal analog quantum search evolution between two orthogonal quantum states is characterized by unit efficiency dynamical…

Quantum Physics · Physics 2020-11-18 Carlo Cafaro , Shannon Ray , Paul M. Alsing

We enhance our quantitative comprehension of the complexity associated with both time-optimal and time sub-optimal quantum Hamiltonian evolutions that connect arbitrary source and target states on the Bloch sphere, as recently presented in…

Quantum Physics · Physics 2025-05-02 Carlo Cafaro , Emma Clements , Abeer Alanazi

The physically allowed quantum evolutions on a single qubit can be described in terms of their geometry. From a simple parameterisation of unital single-qubit channels, the canonical form of all such channels can be given. The related…

Quantum Physics · Physics 2007-05-23 D. K. L. Oi

We examine the pertinent geometric characteristics of entanglement that arise from stationary Hamiltonian evolutions transitioning from separable to maximally entangled two-qubit quantum states. From a geometric perspective, each evolution…

Quantum Physics · Physics 2026-01-16 Carlo Cafaro , James Schneeloch

Geometric phase plays a fundamental role in quantum theory and accounts for wide phenomena ranging from the Aharanov-Bohm effect, the integer and fractional quantum hall effects, and topological phases of matter, including topological…

Quantum Physics · Physics 2022-09-13 Vikash Mittal

We present a unifying variational calculus derivation of Groverian geodesics for both quantum state vectors and quantum probability amplitudes. In the first case, we show that horizontal affinely parametrized geodesic paths on the Hilbert…

Mathematical Physics · Physics 2020-11-16 Carlo Cafaro , Domenico Felice , Paul M. Alsing

In this paper, the quantum corrections to the kinematics of geometry, specifically geodesics, are presented. This is done by employing the path integral over the geodesics. Interestingly, the geodesics do not see any modifications in this…

General Relativity and Quantum Cosmology · Physics 2026-02-03 Nima Khosravi

A central feature of quantum mechanics is that a measurement is intrinsically probabilistic. As a result, continuously monitoring a quantum system will randomly perturb its natural unitary evolution. The ability to control a quantum system…

Quantum Physics · Physics 2014-09-04 S. J. Weber , A. Chantasri , J. Dressel , A. N. Jordan , K. W. Murch , I. Siddiqi
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