Shared Qubit Gate Pulse Shaping for Scalable Quantum Control
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Solution Overview
Problem
Current quantum computing systems face challenges in scaling qubit devices due to the high number of digital-to-analog converters (DACs) required for DC bias and AC pulse control, leading to increased costs, complexity, and power consumption, as well as the inability to apply AC pulses simultaneously to multiple gates.
Innovation Solution
The implementation of pulse control assemblies with two separate capacitors per signal path, allowing for the sharing of DACs and enabling simultaneous application of AC voltage pulses to multiple gates, thereby reducing the overall number of DACs needed and improving scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate DACs are used for each gate control signal, then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple DAC outputs into a single shared DAC by using switch arrays to route control signals. Instead of having separate DACs for each gate, multiple gates share a common DAC resource, reducing the total number of DAC components while maintaining individual control precision through electronic switching.
Solution Approach 2:
The patent implements a universal DAC resource that serves multiple gate control functions simultaneously. The shared DAC can be dynamically allocated to different gates through the switch arrangement, allowing one DAC to perform the functions of multiple dedicated DACs, thereby reducing device complexity and cost.
2Productivity
If more DACs are used for simultaneous AC pulse application, then productivity is improved, but use of energy increases
Solution Approach 1:
The patent merges multiple DAC functions into a single shared DAC resource controlled by switch arrays. This allows simultaneous AC pulse application to multiple gates using one DAC, eliminating the need for multiple energy-consuming DAC components while maintaining the capability to control multiple gates concurrently.
Solution Approach 2:
The patent uses periodic switching of the shared DAC to different gates through the switch arrangement. The DAC can sequentially or simultaneously serve multiple gates by rapidly switching its output, enabling simultaneous pulse application across multiple gates while consuming the energy of a single DAC rather than multiple dedicated DACs.
3Device complexity
If the number of DACs is reduced, then device complexity is decreased, but control precision may deteriorate
Solution Approach 1:
The patent introduces switch arrays as intermediary components between the shared DAC and multiple gates. These switches act as mediators that preserve the control precision of individual gate connections while allowing the DAC resource to be shared. The switch arrangement ensures that each gate receives precise control signals from the shared DAC without cross-interference.
Solution Approach 2:
The patent segments the control signal distribution function by separating the DAC from the gate control paths using switch arrays. This segmentation allows the DAC to be shared while maintaining dedicated, precise control paths to each gate through the switching mechanism, thus preserving control precision while reducing the number of DAC components.
4Reliability
If separate control paths are used for each gate, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the DAC resources while maintaining separate control paths to each gate through switch arrays. This combination approach reduces the number of DAC components (improving reliability by having fewer components that can fail) while preserving individual gate control independence through the switching mechanism.
Solution Approach 2:
The patent creates a universal DAC resource that can serve multiple gates through the switch arrangement. This universal approach improves reliability by reducing the total component count while maintaining the functional independence and control reliability for each gate through electronic switching.
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 solution enables efficient scalable gate control, reducing costs, complexity, and power consumption while allowing for simultaneous AC pulse application to multiple gates, facilitating the scaling of qubit devices in quantum computing systems.
Implementation Method 1
pulse control assemblies with two separate capacitors per signal path
Data Source
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AI summary
Quantum circuit assemblies that employ active pulse shaping in order to be able to control states of a plurality of qubits with signal pulses propagated over a shared signal propagation channel are disclosed. An example quantum circuit assembly includes a quantum circuit component that includes a first qubit, associated with a first frequency to control the state of the first qubit, and a second qubit, associated with a second frequency to control the state of the second qubit. A shared transmission channel is coupled to the first and second qubits. The assembly further includes a signal pulse generation circuit, configured to generate a signal pulse to be propagated over the shared transmission channel to control the state of the first qubit, where the signal pulse has a center frequency at the first frequency, a bandwidth that includes the second frequency, and a notch at the second frequency.