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Related papers: Unitary Transformations using Robust Optimal Contr…

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We theoretically investigate electron spin operations driven by applied electric fields in a semiconductor double quantum dot (DQD). Our model describes a DQD formed in semiconductor nanowire with longitudinal potential modulated by local…

We present a local optimal control strategy to produce desired unitary transformations. Unitary transformations are central to all quantum computational algorithms. Many realizations of quantum computation use a submanifold of states,…

Quantum Physics · Physics 2007-05-23 Shlomo E. Sklarz , David J. Tannor

In this paper, we propose measurement-based quantum computation (MBQC) using two-component Bose-Einstein condensates (BECs). Graph states are naturally introduced by analogy with the qubit case. An arbitrary state of one logical qubit can…

Quantum Physics · Physics 2025-10-01 Genji Fujii

We demonstrate the use of the Variational Quantum Eigensolver (VQE) to simulate solid state crystalline materials. We adapt the Unitary Coupled Cluster ansatz to periodic boundary conditions in real space and momentum space representations…

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

Quantum computation using qubits made of two component Bose-Einstein condensates (BECs) is analysed. The use of BECs allows for an increase of energy scales via bosonic enhancement, resulting in gate operations that can be performed at a…

Quantum Physics · Physics 2012-04-27 Tim Byrnes , Kai Wen , Yoshihisa Yamamoto

We present a novel way to manipulate ultra-cold atoms where four atomic levels are trapped by appropriately tuned optical lattices. When employed to perform quantum computation via global control, this unique structure dramatically reduces…

Quantum Physics · Physics 2013-05-29 Alastair Kay , Jiannis K. Pachos , Charles S. Adams

The optimal quantum control theory is employed to determine electric pulses capable of producing quantum gates with high fidelity (higher than 0.9997). Particularly, these quantum gates were chosen to perform the permutation algorithm (Z.…

Quantum Physics · Physics 2018-03-28 C. M. Rivera-Ruiz , E. F. de Lima , F. F. Fanchini , V. Lopez-Richard , L. K. Castelano

The ability to engineer high-fidelity gates on quantum processors in the presence of systematic errors remains the primary barrier to achieving quantum advantage. Quantum optimal control methods have proven effective in experimentally…

Quantum Physics · Physics 2021-03-30 Thomas Propson , Brian E. Jackson , Jens Koch , Zachary Manchester , David I. Schuster

Within the general context of the architecture in quantum computer design, this paper aims is to provide a general strategy to obtain a block-matrix representation of quantum gates applied to qubits placed in arbitrary positions over an…

Quantum Physics · Physics 2017-11-28 Giuseppe Sergioli

A second-order quantum phase transition in two-species Bose-Einstein condensates of 87Rb atoms coupled by a quantized radiant field is revealed explicitly in terms of the energy spectrum which is obtained in the thermodynamic limit and is…

Strongly Correlated Electrons · Physics 2007-05-23 Gang Chen , J. -Q. Liang , W. -M. Liu

Preparation of non-trivial quantum states without introducing unwanted excitations or decoherence remains a central challenge in utilizing ultracold atomic systems for quantum simulation. We employ optimal control methods to realize fast,…

We propose a scheme for implementing a controlled unitary gate between two distant atoms directly communicating through a quantum transmission line. To achieve our goal, only a series of several coherent pulses are applied to the atoms. Our…

Quantum Physics · Physics 2011-11-09 Jaeyoon Cho , Hai-Woong Lee

Quantum controls realize the unitary or nonunitary operations employed in quantum computers, quantum simulators, quantum communications, and other quantum information devices. They implement the desired quantum dynamics with the help of…

Quantum Physics · Physics 2022-06-02 T S Mahesh , Priya Batra , M. Harshanth Ram

Ultracold neutral atoms in optical lattices are a promising platform for simulating the behavior of complex materials and implementing quantum gates. We optimize collision gates for fermionic Lithium atoms confined in a double-well…

Quantum Gases · Physics 2026-04-10 Jan A. P. Reuter , Juhi Singh , Tommaso Calarco , Felix Motzoi , Robert Zeier

We concretely construct an extension of the controlled-U gate in qudit from some elementary gates. We also construct unitary transformation in two-qudit by means of the extended controlled-U gate and show the universality of it.

Quantum Physics · Physics 2007-05-23 Kunio Funahashi

Preparation of molecular quantum gas promises novel applications including quantum control of chemical reactions, precision measurements, quantum simulation and quantum information processing. Experimental preparation of colder and denser…

Atomic Physics · Physics 2021-04-29 Zhendong Zhang , Liangchao Chen , Kaixuan Yao , Cheng Chin

One of the most remarkable results of quantum mechanics is the fact that many-body quantum systems may exhibit phase transitions even at zero temperature. Quantum fluctuations, deeply rooted in Heisenberg's uncertainty principle, and not…

By moving the pivot of a pendulum rapidly up and down one can create a stable position with the pendulum's bob above the pivot rather than below it. This surprising and counterintuitive phenomenon is a widespread feature of driven systems…

Other Condensed Matter · Physics 2009-11-13 Alessandro Zenesini , Hans Lignier , Donatella Ciampini , Oliver Morsch , Ennio Arimondo

The performance of key tasks in quantum technology, such as accurate state preparation, can be maximized by utilizing external controls and deriving their shape with optimal control theory. For non-pure target states, the performance…

Quantum Physics · Physics 2019-03-13 Daniel Basilewitsch , Christiane P. Koch , Daniel M. Reich