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Li JF, Hu JR, Wan F, He DS. Optimization two-qubit quantum gate by two optical control methods in molecular pendular states. Sci Rep 2022; 12:14918. [PMID: 36050511 PMCID: PMC9437090 DOI: 10.1038/s41598-022-18967-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 08/23/2022] [Indexed: 11/09/2022] Open
Abstract
Implementation of quantum gates are important for quantum computations in physical system made of polar molecules. We investigate the feasibility of implementing gates based on pendular states of the molecular system by two different quantum optical control methods. Firstly, the Multi-Target optimal control theory and the Multi-Constraint optimal control theory are described for optimizing control fields and accomplish the optimization of quantum gates. Numerical results show that the controlled NOT gate (CNOT) can be realized under the control of above methods with high fidelities (0.975 and 0.999) respectively. In addition, in order to examine the dependence of the fidelity on energy difference in the same molecular system, the SWAP gate in the molecular system is also optimized with high fidelity (0.999) by the Multi-Constraint optimal control theory with the zero-area and constant-fluence constraints.
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Affiliation(s)
- Jin-Fang Li
- Department of Physics and Electronic Engineering, Xianyang Normal University, Shaanxi, 712000, China. .,State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai, 200062, China.
| | - Jie-Ru Hu
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai, 200062, China
| | - Feng Wan
- Department of Physics and Electronic Engineering, Xianyang Normal University, Shaanxi, 712000, China
| | - Dong-Shan He
- Department of Physics and Electronic Engineering, Xianyang Normal University, Shaanxi, 712000, China
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2
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Yue W, Wei Q, Kais S, Friedrich B, Herschbach D. Realization of Heisenberg models of spin systems with polar molecules in pendular states. Phys Chem Chem Phys 2022; 24:25270-25278. [DOI: 10.1039/d2cp00380e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ultra-cold polar diatomic or linear molecules, oriented in an external electric field and mutually coupled by dipole–dipole interactions, can be used to realize the exact Heisenberg XYZ, XXZ and XY models without invoking any approximation.
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Affiliation(s)
- Wenjing Yue
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Qi Wei
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Sabre Kais
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Bretislav Friedrich
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Dudley Herschbach
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
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Gonzalo I, Antón MA. Entangling non planar molecules via inversion doublet transition with negligible spontaneous emission. Phys Chem Chem Phys 2019; 21:10523-10531. [PMID: 31070606 DOI: 10.1039/c8cp07764a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We analyze theoretically the entanglement between two non-planar and light identical molecules (e.g., pyramidal NH3) that present inversion doubling due to the internal spatial inversion of their nuclear conformations by tunneling. The peculiarity of this system lies in the simplicity of this type of molecular system in which two near levels can be connected by an allowed electric dipole transition with considerable value of the dipole moment transition and negligible spontaneous emission because the transition is in the microwave or far-infrared range. These properties give place to entanglement states oscillating by free evolution with frequency determined by the dipole-dipole interaction and negligible spontaneous decay, which allows consideration of an efficient quantum Zeno effect by frequent measurements of one of the entangled states. If the molecules are initially both in the upper (or lower) eigenstate, the system evolves under an external radiation field, which can induce oscillations of the generated entangled states, with frequency of the order of the Rabi frequency of the field. For a certain detuning, a symmetric entangled state, which is an eigenstate of the collective system, can be populated, and given its negligible spontaneous emission, could be maintained for a time limited only by external decoherence processes, which could be minimized. Although the data used are those of the NH3 molecule, other molecules could present the same advantageous features.
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Affiliation(s)
- Isabel Gonzalo
- Departamento de Óptica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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Halverson T, Iouchtchenko D, Roy PN. Quantifying entanglement of rotor chains using basis truncation: Application to dipolar endofullerene peapods. J Chem Phys 2018; 148:074112. [DOI: 10.1063/1.5011769] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Tom Halverson
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Dmitri Iouchtchenko
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Wei Q, Cao Y, Kais S, Friedrich B, Herschbach D. Quantum Computation using Arrays of N Polar Molecules in Pendular States. Chemphyschem 2016; 17:3714-3722. [PMID: 27767247 DOI: 10.1002/cphc.201600781] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 10/10/2016] [Indexed: 11/07/2022]
Abstract
We investigate several aspects of realizing quantum computation using entangled polar molecules in pendular states. Quantum algorithms typically start from a product state |00⋯0⟩ and we show that up to a negligible error, the ground states of polar molecule arrays can be considered as the unentangled qubit basis state |00⋯0⟩ . This state can be prepared by simply allowing the system to reach thermal equilibrium at low temperature (<1 mK). We also evaluate entanglement, characterized by concurrence of pendular state qubits in dipole arrays as governed by the external electric field, dipole-dipole coupling and number N of molecules in the array. In the parameter regime that we consider for quantum computing, we find that qubit entanglement is modest, typically no greater than 10-4 , confirming the negligible entanglement in the ground state. We discuss methods for realizing quantum computation in the gate model, measurement-based model, instantaneous quantum polynomial time circuits and the adiabatic model using polar molecules in pendular states.
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Affiliation(s)
- Qi Wei
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Yudong Cao
- Department of Computer Science, Purdue University, West Lafayette, IN, 47907, USA
| | - Sabre Kais
- Department of Chemistry and Physics, Purdue University, West Lafayette, IN, 47907, USA.,Qatar Environment and Energy Research Institute, HBKU, Qatar Foundation, Doha, Qatar
| | - Bretislav Friedrich
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Dudley Herschbach
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, 02138, USA
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6
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Han JX, Hu Y, Jin Y, Zhang GF. Influence of intrinsic decoherence on tripartite entanglement and bipartite fidelity of polar molecules in pendular states. J Chem Phys 2016; 144:134308. [PMID: 27059571 DOI: 10.1063/1.4945384] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An array of ultracold polar molecules trapped in an external electric field is regarded as a promising carrier of quantum information. Under the action of this field, molecules are compelled to undergo pendular oscillations by the Stark effect. Particular attention has been paid to the influence of intrinsic decoherence on the model of linear polar molecular pendular states, thereby we evaluate the tripartite entanglement with negativity, as well as fidelity of bipartite quantum systems for input and output signals using electric dipole moments of polar molecules as qubits. According to this study, we consider three typical initial states for both systems, respectively, and investigate the temporal evolution with variable values of the external field intensity, the intrinsic decoherence factor, and the dipole-dipole interaction. Thus, we demonstrate the sound selection of these three main parameters to obtain the best entanglement degree and fidelity.
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Affiliation(s)
- Jia-Xing Han
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics and Nuclear Energy Engineering, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Yuan Hu
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics and Nuclear Energy Engineering, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Yu Jin
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics and Nuclear Energy Engineering, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
| | - Guo-Feng Zhang
- Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), School of Physics and Nuclear Energy Engineering, Beihang University, Xueyuan Road No. 37, Beijing 100191, China
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Shyshlov D, Berrios E, Gruebele M, Babikov D. On readout of vibrational qubits using quantum beats. J Chem Phys 2014; 141:224306. [PMID: 25494748 DOI: 10.1063/1.4903055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dmytro Shyshlov
- Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201, USA
| | - Eduardo Berrios
- Department of Chemistry, Department of Physics and Center for Biophysics and Computational Biology, University of Illinois, Urbana, Illinois 61801, USA
| | - Martin Gruebele
- Department of Chemistry, Department of Physics and Center for Biophysics and Computational Biology, University of Illinois, Urbana, Illinois 61801, USA
| | - Dmitri Babikov
- Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201, USA
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Affiliation(s)
- Mikhail Lemeshko
- a ITAMP, Harvard-Smithsonian Center for Astrophysics , Cambridge , MA , 02138 , USA
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
| | - Roman V. Krems
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
- d Department of Chemistry , University of British Columbia , BC V6T 1Z1, Vancouver , Canada
| | - John M. Doyle
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
| | - Sabre Kais
- e Departments of Chemistry and Physics , Purdue University , West Lafayette , IN , 47907 , USA
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9
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Zhu J, Kais S, Wei Q, Herschbach D, Friedrich B. Implementation of quantum logic gates using polar molecules in pendular states. J Chem Phys 2013; 138:024104. [DOI: 10.1063/1.4774058] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Wei Q, Kais S, Friedrich B, Herschbach D. Entanglement of polar symmetric top molecules as candidate qubits. J Chem Phys 2011; 135:154102. [DOI: 10.1063/1.3649949] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Qi Wei
- Department of Physics, Texas A & M University, College Station, Texas 77843, USA
| | - Sabre Kais
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Bretislav Friedrich
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Dudley Herschbach
- Department of Physics, Texas A & M University, College Station, Texas 77843, USA
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Wei Q, Kais S, Friedrich B, Herschbach D. Entanglement of polar molecules in pendular states. J Chem Phys 2011; 134:124107. [PMID: 21456645 DOI: 10.1063/1.3567486] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Qi Wei
- Department of Physics, Texas A & M University, College Station, Texas 77843, USA
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Zhu J, Kais S, Rebentrost P, Aspuru-Guzik A. Modified Scaled Hierarchical Equation of Motion Approach for the Study of Quantum Coherence in Photosynthetic Complexes. J Phys Chem B 2011; 115:1531-7. [DOI: 10.1021/jp109559p] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Zhu
- Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Sabre Kais
- Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Patrick Rebentrost
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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