Free-time and fixed end-point multi-target optimal control theory: Application to quantum computing

Mishima, Kenji; Yamashita, Koichi

doi:10.1016/j.chemphys.2010.10.003

Cited by 11 publications

(9 citation statements)

References 34 publications

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“…The other previous version, presented by Mishima and Yamashita [23,25] omits altogether an external static electric field, and takes as qubits the lowest "pure" rotational states (J = 0, M = 0 and J = 1, M = 0) and lowest vibrational states of each molecule.…”

Section: Discussionmentioning

confidence: 99%

“…For instance, to perform a CNOT gate using "pure" rotational states with two lasers took only 10 3 ps [23,25], whereas our use of pendular qubits with one laser required up to 10 5 ps (see Figs. 5 and 6).…”

Section: Discussionmentioning

confidence: 99%

“…[23]. The penalty factor is used to minimize the fluence of the external fields [25]. For the optimized laser pulse E(t) from Eq.…”

Section: At Present It Remains An Open Question Whether In the Presmentioning

confidence: 99%

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Implementation of quantum logic gates using polar molecules in pendular states

Zhu¹,

Kais²,

Qi³

et al. 2013

The Journal of Chemical Physics

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We present a systematic approach to implementation of basic quantum logic gates operating on polar molecules in pendular states as qubits for a quantum computer. A static electric field prevents quenching of the dipole moments by rotation, thereby creating the pendular states; also, the field gradient enables distinguishing among qubit sites. Multi-target optimal control theory is used as a means of optimizing the initial-to-target transition probability via a laser field. We give detailed calculations for the SrO molecule, a favorite candidate for proposed quantum computers. Our simulation results indicate that NOT, Hadamard and CNOT gates can be realized with high fidelity, as high as 0.985, for such pendular qubit states.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Implementation of quantum logic gates using polar molecules in pendular states

Zhu¹,

Kais²,

Qi³

et al. 2013

The Journal of Chemical Physics

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show abstract

“…An experimental application of FRFP-OCTs developed by us for the first time could be expected in the same manner as closed-loop quantum learning control experiments 74 -77 . Finally, as for the recent advancement of free-time and fixed end-point multi-target optimal control theory, the readers are referred to 78 .…”

Section: Discussionmentioning

confidence: 99%

Quantum Computing and Optimal Control Theory

Mishima¹

2012

Some Applications of Quantum Mechanics

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IntroductionIn recent years, quantum computing and quantum information science have become one of the most important and attractive research areas in a variety of disciplines, e. g., mathematics, information science, physics, chemistry, etc 1 . These new kinds of technologies are predicted to be much more advantageous compared with the classical computers and classical information science and the benefit obtained by these technologies is assumed to be beyond measure in our every-day life. For instance, quantum computers are predicted to be able to solve mathematical problems that today's fastest computers could not solve in years. In particular, entanglement or entangled state plays a key role for quantum computing and quantum information processing. For example, arbitrary quantum states of two-level system can be teleported through classical communication with the help of maximally entangled Bell state from one place to other macroscopic distant places (quantum teleportation) 2 , which has no counterpart in classical mechanics. As opposed to the quantum teleportation, classical information can be teleported by using the maximally entangled Bell state (superdense coding) 3 . Needless to say, entanglement is also an essential ingredient in quantum computing 1 . At present, theoretical investigations of the mechanism of quantum computing and quantum information science have become mature although some of the important theoretical problems, e. g., definition of entanglement degree of multipartite systems, have not yet been solved and are still controversial. Yet, one can say that we are now reaching a stage of experimental realizations of quantum computing and quantum information processing proposed and investigated theoretically and numerically. To apply quantum computing and quantum information processing to realistic quantum systems, a number of microscopic quantum systems have been proposed. Just to mention a few, cavity quantum electrodynamics (cavity QED) 4 , trapped ions 5 -7 , neutral atoms trapped in optical lattices 8 , nuclear magnetic resonance (NMR) 9, 10 , superconducting circuits 11 , silicon-based nuclear spin 12 , diamond-based quantum computer 13, 14 are some of the promising candidates of quantum computing devices. However, investigation of utilization of molecular internal degrees of freedom for quantum computing and quantum information science, in particular, electronic, vibrational, and rotational degrees of freedom, is still in its infancy. Although molecules are also quantum systems, very few chemists have yet examined how to use molecular internal degrees of

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“…Research in these fields may have important future applications, for example, in quantum information processing [7][8][9][10]. From a scientific point of view the creation of the molecular quantum gas opens new doors, for instance, in the experimental and theoretical investigation of the cold and ultracold molecular scattering and chemical reactions [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Ultracold collisions between two light indistinguishable diatomic molecules: Elastic and rotational energy transfer in HD+HD

2012

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A close coupling quantum-mechanical calculation is performed for rotational energy transfer in a HD + HD collision at very low energy, down to the ultracold temperatures: T ∼ 10 −8 K. A global six-dimensional H 2 -H 2 potential-energy surface is adopted from a previous work [Boothroyd et al., J. Chem. Phys. 116, 666 (2002)]. State-resolved integral cross sections σ ij →i j (ε kin ) of different quantum-mechanical rotational transitions ij → i j in the HD molecules and corresponding state-resolved thermal rate coefficients k ij →i j (T ) have been computed. Additionally, for comparison, H 2 + H 2 calculations for a few selected rotational transitions have also been performed. The hydrogen and deuterated hydrogen molecules are treated as rigid rotors in this work. A pronounced isotope effect is identified in the cross sections of these collisions at low and ultracold temperatures.

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Free-time and fixed end-point multi-target optimal control theory: Application to quantum computing

Cited by 11 publications

References 34 publications

Implementation of quantum logic gates using polar molecules in pendular states

Implementation of quantum logic gates using polar molecules in pendular states

Quantum Computing and Optimal Control Theory

Ultracold collisions between two light indistinguishable diatomic molecules: Elastic and rotational energy transfer in HD+HD

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