Singlet-state creation and universal quantum computation in NMR using a genetic algorithm

Abstract

Experimental implementation of a quantum algorithm requires unitary operator decomposition. Here we treat the unitary operator decomposition as an optimization problem and use Genetic Algorithm, a global optimization method inspired by nature's evolutionary process for operator decomposition. As an application, we apply this to NMR Quantum Information Processing and find a probabilistic way of doing universal quantum computation using global hard pulses. We also demonstrate efficient creation of singlet state (as a special case of Bell state) directly from thermal equilibrium using an optimum sequence of pulses.

Fast and accurate quantification using Genetic Algorithm optimized 1H-13C refocused constant-time INEPT

“…Multiple narrow white bars in the 13 C channel is 180°composite pulse, which reduce the off-resonance effects as shown in [9]. The first two 90°pulses on carbon channel (purge) are to remove the native 13 C magnetization. Gradient strengths are 45.4 G/cm (for G 1 and G 2 ) and 53 G/cm (for G 3 ) with 4 ms (for G 1 and G 2 ) and 200 us (for G 3 ).…”

“…GAs are attractive in engineering design and applications because they are easy to use and are likely to find the globally best solution, which is superior to any other design or solution [12]. We have recently used GA for optimal design of various one and two qubit quantum gates by NMR [13]. Genetic Algorithm has been used in NMR for designing new experiments [14], for improving excitation and inversion accuracy of RF pulses [15] and pulse sequence optimization [16].…”

“…In general spectral peak intensities are modulated by system parameters such as coupling strength, relaxation, mobility of molecule and number of protons attached. These quantification criteria naturally select 1 H decoupled 13 C NMR for complex mixture quantification. Large experimental time, because of the less sensitive 13 C nuclei, is the major disadvantage of traditional 13 C quantification experiment.…”

“…These quantification criteria naturally select 1 H decoupled 13 C NMR for complex mixture quantification. Large experimental time, because of the less sensitive 13 C nuclei, is the major disadvantage of traditional 13 C quantification experiment. To overcome this, experiments utilizing polarization transfer from abundant high sensitive protons to 13 C (APT, NOE, INEPT) [4][5][6] are used, but they are sensitive to system parameters.…”

Efficient experimental design of high-fidelity three-qubit quantum gates via genetic programming

“…GAs borrow their optimization protocol from the basic tenets of evolutionary biology, wherein the breeding strategy of a population is to increase the fitness levels and offspring-producing capability of individuals by crossing over of genetic information [40]. In quantum information processing, GAs have been used to optimize quantum algorithms [41][42][43] and quantum entanglement [44], for optimal dynamical decoupling [45], and to optimize unitary transformations for a general quantum computation [46,47].…”