Towards Quantum-Limited Cryogenic Amplification for Multi-Qubit Platforms
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Here we present the development of the building blocks of a Josephson parametric amplifier (JPA), namely the superconducting quantum interference device (SQUID) and the inductive pick-up coil that permits current coupling from a quantum dot into the SQUID. We also discuss our efforts in making depletion mode quantum dots using delta doped GaAs quantum wells. Because quantum dot based spin qubits utilize very low-level (~10 - 100pA), short duration (1ms - 1μs) current signals for state preparation and readout, these systems require close proximity cryogenic amplification to prevent signal corruption. Common amplification methods in these semiconductor quantum dots rely on heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs) to amplify the readout signal from a single qubit. The state of the art for HBTs and HEMTs produce approximately 10µW of power when operating at high bandwidths. For few-qubit systems this level of heat dissipation is acceptable. However, for scaling up the number of qubits to several hundred or a thousand, the heat load produced in a 1 to 1 amplifier to qubit arrangement would overload the cooling capacity of a common dilution refrigerator, which typically has a cooling power of ~100µW at its base temperature. Josephson parametric amplifiers have been shown to dissipate ~1pW of power with current sensitivies on par with HBTs and HEMTs and with bandwidths 30 times that of HBTs and HEMTs, making them attractive for multi-qubit platforms. In this report we describe in detail the fabrication process flow for developing inductive pick-up coils and the fabrication and measurement of NbTiN and A1/A1Ox/A1 SQUIDs.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1569518
- Report Number(s):
- SAND-2019-11768R; 679850
- Country of Publication:
- United States
- Language:
- English
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