Presentation Information
[EDP2-10]Energy loss functions for electronic mode of Si, Al, and TiN substrate materials used in quantum computing based on first-principles electronic structure calculations
*Takuya Sekikawa1, Takeshi Kai1 (1. Japan Atomic Energy Agency (Japan))
Keywords:
SQUID,q-bit,Radiation effect
[Purpose]
The engineering applications of superconductivity are diverse, but among them, the application of superconducting quantum bits to quantum computers has become increasingly important in recent years. To achieve superconductivity, which is necessary for the realization of superconducting quantum bits (qubits), extremely low temperatures of around 1 to 5 K are required. However, at such extremely low temperatures, even the heat generated by environmental radiation such as muons can destroy the superconducting state. As a result, the evaluation of quantum computing is currently very difficult.
[Method]
To solve this problem, it is first necessary to perform radiation transport and heat transfer calculations for superconducting qubits. However, current radiation transport calculation codes are mainly based on calculations using room temperature dielectric functions, and in order to perform calculations at extremely low temperatures, it is necessary to reconstruct calculation methods based on energy loss functions at extremely low temperatures.
[Results]
In this study, as a first step toward performing radiation transport and heat transfer calculations in the microdomain of superconducting qubits (~μm), we calculated the energy loss functions of Si, Al, and TiN used in the qubits at extremely low temperatures. Using the first-principles calculation software OpenMX , the results for Si, Al and TiN were compared at 1 K and 300 K in Fig. 1 which showed that the results of Si unchanged, while that of Al and TiN exhibited little change.
[Consideration]
From these results, no temperature dependence of energy loss functions for electronic mode was indicated, however, that for phonon mode would appear.
[Conclusion]
Our studies included in the phonon mode would be expected to contribute to the development of radiation-resistant technology for superconducting qubits.
The engineering applications of superconductivity are diverse, but among them, the application of superconducting quantum bits to quantum computers has become increasingly important in recent years. To achieve superconductivity, which is necessary for the realization of superconducting quantum bits (qubits), extremely low temperatures of around 1 to 5 K are required. However, at such extremely low temperatures, even the heat generated by environmental radiation such as muons can destroy the superconducting state. As a result, the evaluation of quantum computing is currently very difficult.
[Method]
To solve this problem, it is first necessary to perform radiation transport and heat transfer calculations for superconducting qubits. However, current radiation transport calculation codes are mainly based on calculations using room temperature dielectric functions, and in order to perform calculations at extremely low temperatures, it is necessary to reconstruct calculation methods based on energy loss functions at extremely low temperatures.
[Results]
In this study, as a first step toward performing radiation transport and heat transfer calculations in the microdomain of superconducting qubits (~μm), we calculated the energy loss functions of Si, Al, and TiN used in the qubits at extremely low temperatures. Using the first-principles calculation software OpenMX , the results for Si, Al and TiN were compared at 1 K and 300 K in Fig. 1 which showed that the results of Si unchanged, while that of Al and TiN exhibited little change.
[Consideration]
From these results, no temperature dependence of energy loss functions for electronic mode was indicated, however, that for phonon mode would appear.
[Conclusion]
Our studies included in the phonon mode would be expected to contribute to the development of radiation-resistant technology for superconducting qubits.