W911NF-22-S-0006: Thermalization of microwave components for improved qubit coherence
Abstract
For public release Thermalization of microwave components for improved qubit coherence Program Manager: T. R. Govindan, ARO Quantum Information Science PI: Shyam Shankar, University of Texas at Austin Co-PI: Srivatsan Chakram, Rutgers University Co-PI: Li Shi, University of Texas at Austin Dielectric materials such as teflon, printed circuit board, Eccosorb etc. are commonly found in solid-state quantum computing setups operated at below 20 mK temperature. It is widely believed that these dielectrics thermalize poorly due to vanishing thermal conductivity at low temperatures. As a result, these materials remain at elevated temperatures of the order of 50 to 100 mK, which adversely affect qubit properties such as coherence times and excited state population. Many groups have attempted to combat these adverse effects by sacrificing qubit readout fidelity, which hurts the prospects for achieving fault-tolerant quantum computing as high-quality readout is an essential primitive for quantum error correction. Other attempts to improve coherence use ad-hoc filtering of thermal noise with no quantitative understanding of the expected performance. The results of such trial-and-error approaches to filtering have been mixed and often not reproduced when translated between experiments. Here we propose to directly measure the thermalization properties of dielectric materials with a superconducting quantum hardware setup consisting of a multi-mode three-dimensional cavity, a transmon qubit, an auxiliary coupler mode and a readout resonator. This thermalization data, along with thermal transport modeling, will be subsequently used to design an assembly where a superconducting processor with multiple transmon qubits and readout resonators are integrated with filtering to improve qubit coherence by an order of magnitude without sacrificing readout fidelity. We will model the expected qubit relaxation and coherence times for such an assembly and subsequently build and test its performance. The medium-term impact of our work would be to show how we can improve qubit coherence while maintaining the ability to perform fast and high-fidelity, quantum non-demolition readout of transmon qubits.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 27, 2023
- Source ID
- W911NF2310251
Entities
People
- Shyam Shankar
Organizations
- Army Contracting Command
- National Security Agency
- University of Texas at Austin