Dr Mustafa Bakr

Abstract:

Using quantum systems with more than two levels, or qudits, can scale the computational space of quantum processors more efficiently than using qubits, which may offer an easier physical implementation for larger Hilbert spaces. However, individual qudits may exhibit larger noise, and algorithms designed for qubits require to be recompiled to qudit algorithms for execution. In this work, we implemented a two-qubit emulator using a 4-level superconducting transmon qudit for variational quantum algorithm applications and analyzed its noise model. The major source of error for the variational algorithm was readout misclassification error and amplitude damping. To improve the accuracy of the results, we applied error-mitigation techniques to reduce the effects of the misclassification and qudit decay event. The final predicted energy value is within the range of chemical accuracy.

Abstract:

This article presents a new filter design for arbitrary placement of real frequency transmission zeros in triple-mode filters, allowing for either asymmetric or symmetric responses. Triple-mode filters can be viewed, in general, as a series combination of coupled resonators with non-adjacent couplings, allowing for the realisation of transmission zeros. The strength and phase of couplings dictate the transmission zeros locations. The arbitrary placement of transmission zeros requires controlling all amplitude and phase rations, i.e., the ability to realise both negative and positive couplings. In general, this necessitates the use of capacitive and inductive probe structures complicating the construction and hence increasing the filter cost. The method presented in this article enables arbitrary placement of transmission zeros using only inductive or only capacitive couplings structures. In addition, broadband filtering characteristics can be realised using triple-mode filters. Examples of several narrow and broadband bandpass filters are given indicating that this method is valid for most triple-mode structures.