April 2023

Abstracts of the Quantum Center Lunch Seminar

Date: Thursday, April 6, 2023
Place: ETH Zurich, Hönggerberg, HPF G 6
Time: 12:00 - 13:30

Schrödinger cat states of a 16-microgram mechanical oscillator

Marius Bild - Hybrid Quantum Systems (Chu group), ETH Zurich

While the principle of superposition in quantum physics is routinely validated for microscopic systems, it is still unclear why we do not observe macroscopic objects to be in superpositions of states that can be distinguished by some classical property. I will present our experiments, that harness the resonant Jaynes-Cummings interaction between a high overtone resonator mode of a bulk acoustic wave resonator and a superconducting qubit, to demonstrate the preparation of Schrödinger cat states of motion. In such a state, the constituent atoms oscillate in a superposition of two opposite phases with an effective oscillating mass of 16𝜇g. Making use of the circuit quantum acoustodynamics toolbox we have developed, we furthermore show control over amplitudes and phases of the created Schrödinger cat states, and investigate their decoherence dynamics by observing the disappearance of Wigner negativities. Our results can find applications in continuous variable quantum information processing and in fundamental investigations of quantum mechanics in massive systems.

Towards large scale quantum computing - a many qubit ion trap at room temperature

Philip Leindecker - Ion Trap Quantum Computing (Hempel group), ETHZ-PSI Quantum Computing Hub

Large scale quantum computing is subject to extensive research and the ideal platform for general purpose quantum computers has yet to be found. Trapped ions as qubits excel in terms of gate fidelity and coherence times but so far systems have mostly been limited to only a small number of qubits. Our system is designed to support a linear chain of up to 50 ions which can be individually addressed, providing a versatile platform with many qubits and a high level of control. At the heart of the system is a 3-dimensional ion trap consisting of gold coated laser machined glass. The trap operates in ultra-high vacuum at room temperature. Individual addressing is implemented using a waveguide array. One application of this system is research towards large distance error correction, eventually enabling fault tolerant quantum computation. The high level of control is furthermore advantageous for the simulation of complex Hamiltonians, effectively performing quantum simulation at scale. Lastly, the segmented electrodes of the trap allow splitting of the ion chain into multiple segments for parallel quantum processing.