Grooved Quantum Attenuator on High-Conductivity Substrates
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Solution Overview
Problem
Existing dissipative devices for quantum applications, such as those described in Yeh et al., lack efficiency in both microwave and thermalization aspects, and struggle to achieve a good trade-off between thermal and microwave performance, leading to reduced coherence times and increased thermal noise in superconducting qubits.
Innovation Solution
A dissipative device comprising a high-thermal conductivity substrate with grooved transmission lines filled with powders like Nichrome, copper, platinum, or silver, and copper heat sinks to reduce metal-substrate interfacial thermal resistance and absorb heat, thereby improving thermalization and reducing thermal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional dissipative devices are used, then thermal noise is reduced, but thermalization efficiency deteriorates
Solution Approach 1:
The patent employs porous copper heat sinks with controlled porosity (30-70%) to enhance thermalization. The porous structure increases surface area for thermal contact while maintaining thermal conductivity, allowing efficient heat removal from the transmission lines without increasing device complexity
Solution Approach 2:
The patent uses composite structures combining copper powder (for thermal conductivity) with binding agents to create heat sink material with optimized properties. The composite copper powder mixture achieves both high thermal conductivity and mechanical integrity, resolving the contradiction between thermalization efficiency and device reliability
2Object-affected harmful factors
If substrate thermal conductivity is increased, then thermal noise is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent changes the substrate material parameter from conventional low-conductivity materials to high-thermal-conductivity materials (diamond, cubic boron nitride, or highly oriented pyrolytic graphite) with thermal conductivity exceeding 200 W/mK. This parameter change reduces thermal noise while the integrated design keeps manufacturing complexity manageable
3Reliability
If copper heat sinks are added, then thermalization is improved, but device complexity increases
Solution Approach 1:
The patent merges the heat sink function with the substrate structure by integrating copper heat sinks directly into the substrate's ground planes and thermal management layers. This consolidation improves thermalization while avoiding the need for separate, complex heat sinking components
Solution Approach 2:
The copper heat sinks serve multiple functions: they provide thermal management, act as ground planes for RF shielding, and serve as thermal pathways to the cold stage. This multi-functionality improves thermalization without proportionally increasing device complexity
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
The solution enhances thermalization and reduces thermal noise, leading to longer coherence times and improved performance of quantum computers by minimizing thermal noise and Joule heating, while maintaining effective microwave response.
Implementation Method 1
The one or more copper heat sinks can be formed adjacent to the one or more grooved transmission lines... The one or more heat sinks can absorb heat from the one or more resistors
Implementation Method 2
The one or more grooved transmission lines can comprise a powder substance... The one or more grooved transmission lines can facilitate thermalization to reduce a metal-substrate interfacial thermal resistance
Data Source
AI summary
Techniques for facilitating reduced thermal resistance attenuator on high-thermal conductivity substrates for quantum applications are provided. A device can comprise a substrate that provides a thermal conductivity level that is more than a defined thermal conductivity level. The device can also comprise one or more grooved transmission lines formed in the substrate. The one or more grooved transmission lines can comprise a powder substance. Further, the device can comprise one or more copper heat sinks formed in the substrate. The one or more copper heat sinks can provide a ground connection. Further, the one or more copper heat sinks can be formed adjacent to the one or more grooved transmission lines.