On-Chip SQUID Magnetometer for Quantum Processor Field Compensation
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Solution Overview
Problem
Current methods for measuring magnetic fields in superconducting quantum processors face challenges such as magnetic field gradients, limited sensitivity, and power dissipation issues, particularly when magnetometers are not integrated with the processor chip, leading to discrepancies and inefficiencies.
Innovation Solution
The integration of superconducting quantum interference devices (SQUIDs) directly on the processor chip, which are sensitive to magnetic fields orthogonal to the chip's surface, along with compensation coils and controllable heaters, allows for precise measurement and tuning of local magnetic fields, addressing sensitivity and power consumption issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetometers are not integrated with the processor chip, then device complexity is reduced, but measurement precision deteriorates due to magnetic field gradients and limited sensitivity
Solution Approach 1:
The patent integrates magnetometers directly onto the processor chip, combining two separate devices into one unified structure. This integration eliminates the need for separate magnetometer housing, power supply, and signal processing circuits, thereby improving measurement precision through direct coupling while managing device complexity through shared infrastructure.
Solution Approach 2:
The patent transitions from external magnetometer placement to on-chip integration, effectively moving the measurement function into a new dimensional space within the chip architecture. This allows magnetic field sensing to occur at the same physical location as the processor operations, eliminating spatial discrepancies that cause measurement errors.
2Loss of energy
If external magnetometers are used, then device complexity is reduced, but power dissipation increases due to separate power supply and signal processing requirements
Solution Approach 1:
By merging the magnetometer with the processor chip, the patent enables shared power supply circuits and signal processing resources. The integrated design allows both devices to draw power from the same voltage regulators and use common ground references, reducing redundant power consumption and eliminating separate power management hardware.
Solution Approach 2:
The integrated magnetometer-processor chip serves multiple functions simultaneously: it processes quantum computations while continuously monitoring magnetic field conditions. This multi-functionality eliminates the need for separate dedicated magnetometer power supplies and signal processing chains, thereby reducing overall power dissipation.
3Measurement precision
If magnetometers are not integrated with the processor chip, then manufacturing precision requirements are reduced, but measurement accuracy deteriorates due to field gradients
Solution Approach 1:
The integration process merges magnetometer fabrication with existing processor chip manufacturing workflows. By using the same lithography, deposition, and etching tools already calibrated for processor fabrication, the patent achieves precise magnetometer placement and orientation without requiring entirely new manufacturing capabilities, thus managing precision requirements while improving measurement accuracy.
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
This approach enables highly localized and sensitive measurement of magnetic fields, reducing power dissipation and eliminating discrepancies due to field gradients, thereby improving the accuracy and efficiency of magnetic field compensation in superconducting quantum processors.
Implementation Method 1
a first superconducting quantum interference device (SQUID) comprising a closed superconducting current path formed by a planar loop of material that is superconducting below a critical temperature
Implementation Method 2
the closed superconducting current path is interrupted by at least one Josephson junction
Data Source
AI summary
SQUIDs may detect local magnetic fields. SQUIDS of varying sizes, and hence sensitivities may detect different magnitudes of magnetic fields. SQUIDs may be oriented to detect magnetic fields in a variety of orientations, for example along an orthogonal reference frame of a chip or wafer. The SQUIDS may be formed or carried on the same chip or wafer as a superconducting processor (e.g., a superconducting quantum processor). Measurement of magnetic fields may permit compensation, for example allowing tuning of a compensation field via a compensation coil and/or a heater to warm select portions of a system. A SQIF may be implemented as a SQUID employing an unconventional grating structure. Successful fabrication of an operable SQIF may be facilitated by incorporating multiple Josephson junctions in series in each arm of the unconventional grating structure.