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We study the optimal quantum control of heteronuclear two-qubit systems described by a Hamiltonian containing both nonlocal internal drift and local control terms. We derive an explicit formula to compute the minimum time required to steer…

Quantum Physics · Physics 2013-11-07 Bin Li , Zu-Huan Yu , Shao-Ming Fei , XianQing Li-Jost

We present an empirical strategy to determine the Hamiltonian dynamics of a two-qubit system using only initialization and measurement in a single fixed basis. Signal parameters are estimated from measurement data using Bayesian methods…

Quantum Physics · Physics 2009-10-01 S. G. Schirmer , D. K. L. Oi

Despite significant progress in theoretical and laboratory quantum control, engineering quantum systems remains principally challenging due to manifestation of noise and uncertainties associated with the field and Hamiltonian parameters. In…

Quantum Physics · Physics 2021-12-15 Andrew Koswara , Vaibhav Bhutoria , Raj Chakrabarti

What is the time-optimal way of using a set of control Hamiltonians to obtain a desired interaction? Vidal, Hammerer and Cirac [Phys. Rev. Lett. 88 (2002) 237902] have obtained a set of powerful results characterizing the time-optimal…

Quantum Physics · Physics 2009-11-10 Henry L. Haselgrove , Michael A. Nielsen , Tobias J. Osborne

Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%. Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and…

The process of measuring a two-level quantum system was examined by applying Hamiltonian formalism. For the measurement of an observable that does not commute with the system Hamiltonian, a non-trivial relationship among the strength of…

Quantum Physics · Physics 2011-05-24 Takayuki Miyadera

Recent work by Mania et al. has proved that certainty equivalent control achieves nearly optimal regret for linear systems with quadratic costs. However, when parameter uncertainty is large, certainty equivalence cannot be relied upon to…

Optimization and Control · Mathematics 2020-01-01 Jack Umenberger , Thomas B. Schon

This work studies the feasibility of optimal control of high-fidelity quantum gates in a model of interacting two-level particles. One particle (the qubit) serves as the quantum information processor, whose evolution is controlled by a…

There is a fundamental limit to what is knowable about atomic and molecular scale systems. This fuzziness is not always due to the act of measurement. Other contributing factors include system parameter uncertainty, functional uncertainty…

Quantum Physics · Physics 2022-10-31 Randa Herzallah , Abdessamad Belfakir

Engineering effective Hamiltonians is essential for advancing quantum technologies including quantum simulation, sensing, and computing. This paper presents a general framework for effective Hamiltonian engineering, enabling robust,…

Quantum Physics · Physics 2026-04-07 Jiahui Chen , David Cory

An overview and synthesis of results and criteria for open-loop controllability of Hamiltonian quantum systems obtained using Lie group and Lie algebra techniques is presented. Negative results for open-loop controllability of dissipative…

Quantum Physics · Physics 2007-05-23 S. G. Schirmer , I. C. H. Pullen , A. I. Solomon

The efficient validation of quantum devices is critical for emerging technological applications. In a wide class of use-cases the precise engineering of a Hamiltonian is required both for the implementation of gate-based quantum information…

Quantum Physics · Physics 2019-11-20 Agnes Valenti , Evert van Nieuwenburg , Sebastian Huber , Eliska Greplova

We introduce a new approach for the robust control of quantum dynamics of strongly interacting many-body systems. Our approach involves the design of periodic global control pulse sequences to engineer desired target Hamiltonians that are…

Quantum Physics · Physics 2020-07-08 Joonhee Choi , Hengyun Zhou , Helena S. Knowles , Renate Landig , Soonwon Choi , Mikhail D. Lukin

We build upon recent work on using Machine Learning models to estimate Hamiltonian parameters using continuous weak measurement of qubits as input. We consider two settings for the training of our model: (1) supervised learning where the…

Quantum Physics · Physics 2025-02-17 Kris Tucker , Amit Kiran Rege , Conor Smith , Claire Monteleoni , Tameem Albash

We theoretically study specific schemes for performing a fundamental two-qubit quantum gate via controlled atomic collisions by switching microscopic potentials. In particular we calculate the fidelity of a gate operation for a…

Quantum Physics · Physics 2009-10-31 T. Calarco , E. A. Hinds , D. Jaksch , J. Schmiedmayer , J. I. Cirac , P. Zoller

Robust performance of control schemes for open quantum systems is investigated under classical uncertainties in the generators of the dynamics and nonclassical uncertainties due to decoherence and initial state preparation errors. A…

Optimization and Control · Mathematics 2024-06-24 Sophie G. Schirmer , Frank C. Langbein , Carrie A. Weidner , Edmond Jonckheere

We examine the effectiveness and resilience of achieving quantum gates employing three approaches stemming from quantum control methods: counterdiabatic driving, Floquet engineering, and inverse engineering. We critically analyse their…

Quantum Physics · Physics 2023-08-30 Eoin Carolan , Barış Çakmak , Steve Campbell

The construction of two-qubit gates appropriate for universal quantum computation is of enormous importance to quantum information processing. Building such gates is dependent on accurate knowledge of the interaction dynamics between two…

Quantum Physics · Physics 2009-11-11 Simon J. Devitt , Jared H. Cole , Lloyd C. L. Hollenberg

In laboratory and numerical experiments, physical quantities are known with a finite precision and described by rational numbers. Based on this, we deduce that quantum control problems both for open and closed systems are in general not…

Quantum Physics · Physics 2025-02-21 Denys I. Bondar , Alexander N. Pechen

Precision control of quantum systems is the driving force for both quantum technology and the probing of physics at the quantum and nano-scale. We propose an implementation independent method for in situ quantum control that leverages…

Quantum Physics · Physics 2015-07-14 Christopher Ferrie , Osama Moussa