On-Chip TLS Filtering for Qubit Energy Loss Control
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Solution Overview
Problem
Two-level system (TLS) defects cause fluctuations in T1 relaxation times and coherence times of quantum systems, leading to decreased performance and increased error rates in quantum devices due to energy leakage and decoherence.
Innovation Solution
An on-chip filtering system with an electrode and electrical filter, connected to a voltage source, is used to shift the resonant frequency of TLS defects, reducing their impact on qubits by applying an electric field to tune their frequency and prevent energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrode is placed in proximity to the qubit device to apply electric field for tuning TLS frequency, then TLS impact on qubit is reduced, but energy leakage from qubit to electrode (Purcell loss) increases
Solution Approach 1:
An electrical filter is introduced as an intermediary component between the electrode and the qubit device. The filter is tuned to reflect signals at the qubit frequency, blocking energy leakage from the qubit to the electrode while allowing the electrode to apply the necessary electric field for TLS frequency tuning. This mediator resolves the contradiction by permitting the beneficial electric field application while preventing the harmful energy loss.
2Duration of action of stationary object
If voltage is applied to electrode to shift TLS resonant frequency, then coherence time is improved, but device complexity increases
Solution Approach 1:
The system adjusts the resonant frequency parameter of TLS defects by applying voltage to the electrode, which changes the electric field environment experienced by the TLS. This parameter change shifts the TLS frequency away from the qubit operating frequency, thereby improving coherence time. The electrical filter ensures this parameter adjustment does not cause energy loss.
3Loss of energy
If electrical filter is added to prevent energy leakage, then qubit energy is preserved, but manufacturing precision requirements increase
Solution Approach 1:
The electrical filter is designed as a replicated structure with standardized geometry and material properties. By using a copying approach where the filter dimensions and characteristics are precisely defined and replicated, the system achieves the necessary frequency selectivity without requiring unique, high-precision custom manufacturing for each component. The filter tuning is achieved through standardized design parameters rather than custom precision work.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances qubit performance by minimizing energy leakage and decoherence, thereby improving T1 times and reducing gate error rates.
Implementation Method 1
The voltage source can control a voltage to the electrode to shift a resonant frequency of the one or more defects to reduce two level system (TLS) impact on the qubit device
Implementation Method 2
The electrical filter can comprise a filter tuned to reflect signals at a frequency of a transmon qubit of the qubit device
Data Source
AI summary
Systems and techniques that facilitate controlling TLS via on-chip filtering to prevent qubit energy loss are provided. In various embodiments, a system can comprise a quantum device including a qubit device on a substate. In various embodiments, the quantum device can include an electrode placed in proximity to the qubit device. In various embodiments, an electrical filter can be connected to the electrode. In various embodiments, the quantum device can comprise a voltage source that can be connected to the electrode via the electrical filter. In various embodiments, the voltage source can control a voltage to the electrode to shift a resonant frequency of one or more defects to reduce two level system (TLS) impact on the qubit device.