That’s if you’re telling time by the Doomsday Clock, which isn’t an actual clock, of course. These developments have resulted to three publications.It’s almost midnight, and it has been for 75 years. We were able to accomplish these goals and in particular we have reached some significant milestones in defining the QC efficiency and development of the QC-simulator. In specific goals of the project were to (a) develop experimental and sample based methods to improve the performance of NMR-QC, (b) define and estimate actual time cost or efficiency of a QCs, and (c) construct a comprehensive simulator of QC based on the principles of ensemble quantum computing. The PI's play an integral role in promoting the work performed using the LDRD funded project and hence acquire the attention within the lab as well outside. Our success in the proposal is in part responsible for the formation of the laboratory-wide exploratory group on ''quantum computing and information''. Three years ago, when we initiated proposal on NMR-QC, the foremost of the aim is to develop quantum computing as part of LLNL research programs and hence cultivate an interdisciplinary working group in the area of quantum computing. The logic gates and algorithms correspond to set of instructions containing radio frequency (r.f) pulses and delays that manipulate the qubits and the final spectrum reflects the outcome of the algorithm. In NMR quantum computing, the spins with non-zero nuclear moments (spin 1/2 nuclei such as C) in an organic molecule dissolved in a solvent constitute the required qubits. Thus, quantum computing based on NMR is considered as ensemble quantum computing. NMR-QC differs from other implementations in one important way that it is not a single QC, but a statistical ensemble of them. Nuclear magnetic resonance (NMR) is uniquely capable of constructing small QCs and several algorithms have been implemented successfully. These methods include, trapped ions, cavity-QED, coupled quantum dots, Josephson junctions, spin resonance transistors, linear optics and nuclear magnetic resonance. The algorithms that were of only theoretical interest as recently, until several methods were proposed to build an experimental QC. A variety of algorithms have been developed recently, most notably Shor's algorithm for factorizing long numbers into prime factors in polynomial time and Grover's quantum search algorithm. Quantum computers offer the potentially superior prospect of solving computational problems that are intractable to classical computers such as efficient database searches and cryptography. As the size of the logic gates become smaller toward the level of atomic dimensions, the performance of such a system is no longer considered classical but is rather governed by quantum mechanics. The expansion more » of modern computers has been driven by the developments of faster, smaller and cheaper logic gates. Bits are connected together by logic gates to form logic circuits to implement complex logical operations. In classical computers, the basic unit of information is the bit, which can take a value of either 0 or 1. In a QC, binary information embodied in a quantum system, such as spin degrees of freedom of a spin-1/2 particle forms the qubits (quantum mechanical bits), over which appropriate logical gates perform the computation. The power of a quantum computer (QC) relies on the fundamental concept of the superposition in quantum mechanics and thus allowing an inherent large-scale parallelization of computation. Since the quadrupolar coupling is several orders of magnitude greater than the coupling in weakly coupled spin-(1/2) nuclei, the gate time decreases, increasing the clock speed of the quantum computer. To the best of our knowledge, this method has been implemented for the first time in quadrupolar systems. The controlled-NOT operation needed to implement this algorithm has been implemented here by evolution under the quadrupolar Hamiltonian. more » We implement the Deutsch-Jozsa algorithm on a spin-(3/2) (2 qubit) system. Second, we use evolution under quadrupolar coupling to implement multiqubit gates. First, we implement a quantum algorithm that needs coherent superposition of states. In this paper we report two developments. So far, creation of pseudopure states and logic gates has been demonstrated in such systems using transition selective radio-frequency pulses. Such systems have multiple qubits per nuclei and large quadrupolar couplings resulting in well separated lines in the spectrum. Nuclei with spin>1/2 oriented in liquid-crystalline matrices is another possibility. Physical implementation of quantum-information processing by liquid-state nuclear magnetic resonance, using weakly coupled spin-(1/2) nuclei of a molecule, is well established.
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