Efficient reverse engineering of one-qubit filter functions with dynamical invariants

We derive an integral expression for the filter-transfer function of an arbitrary one-qubit gate through the use of dynamical invariant theory and Hamiltonian reverse engineering. We use this result to define a cost functional which can be efficiently optimized to produce one-qubit control pulses that are robust against specified frequency bands of the noise power spectral density. We demonstrate the utility of our result by generating optimal control pulses that are designed to suppress broadband detuning and pulse amplitude noise. We report an order of magnitude improvement in gate fidelity in comparison with known composite pulse sequences. More broadly, we also use the same theoretical framework to prove the robustness of nonadiabatic geometric quantum gates under specific error models and control constraints

Conditions for Equivalent Noise Sensitivity of Geometric and Dynamical Quantum Gates

Geometric quantum gates are often expected to be more resilient than dynamical gates against certain types of error, which would make them ideal for robust quantum computing. However, this is still up for debate due to seemingly conflicting results in the literature. Here we use dynamical invariant theory in conjunction with filter functions in order to analytically characterize the noise sensitivity of an arbitrary quantum gate. For any control Hamiltonian that produces a geometric gate, we find that, under certain common conditions, one can construct another control Hamiltonian that produces an equivalent dynamical gate with identical noise sensitivity (as characterized by the filter function). Our result holds for a Hilbert space of arbitrary dimensions, but we illustrate our result by examining experimentally relevant single-qubit scenarios and providing explicit examples of equivalent geometric and dynamical gates

Role of Smart Cities in Creating Sustainable Cities and Communities: A Systematic Literature Review

YesSmart cities can help in achieving UN SDG. This research carries out a comprehensive analysis of the role of smart cities on creating sustainable cities and communities, which is one of 17 UN sustainable goals. Current research focuses on number of aspect of sustainable environment such as renewable and green energy, energy efficiency, environmental monitoring, air quality, and water quality. This study provides a valuable synthesis of the relevant literature on smart cities by analysing and discussing the key findings from existing research on issues of smart cities in creating sustainable cities and communities. The findings of this study can provide an informative framework for research on smart cities for academics and practitioners