Quantum Error Correction Code for Coherent Noise
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Solution Overview
Problem
In quantum computing, coherent noise leads to decoherence and loss of information, limiting the efficiency and reliability of quantum computations, as existing error correction methods are not effective in mitigating this type of noise passively.
Innovation Solution
A quantum computing system is designed to operate within a subspace of a full n-qubit Hilbert space, where the subspace is unperturbed by coherent noise, using a method that relocates errors within the larger Hilbert space, with the noise acting as an identity operator on the protected subspace, effectively maintaining coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active error correction methods are used to address coherent noise, then quantum information loss can be reduced, but the system complexity and computational overhead increase
Solution Approach 1:
The patent converts the harmful coherent noise into a beneficial effect by designing a quantum code where the noise operator commutes with the stabilizer group. This allows the noise to act as an identity operator on the code space, transforming the noise from a destructive force into a harmless operation that preserves quantum information without requiring active correction.
Solution Approach 2:
The patent changes the parameter of the quantum code by selecting a specific stabilizer group and code space structure that is invariant under coherent noise operations. By carefully choosing the code parameters (stabilizer generators, code space dimension), the system achieves noise obliviousness where the noise does not affect the encoded information.
2Reliability
If quantum measurements are performed to correct errors, then decoherence can be mitigated, but the act of measurement itself causes decoherence
Solution Approach 1:
The patent turns the harmful effect of measurement-induced decoherence into a benefit by designing a code where the noise operator commutes with the stabilizer group. This allows the noise to act as an identity operator on the code space, transforming the noise from a destructive force into a harmless operation that preserves quantum information without requiring active correction.
3Productivity
If the full n-qubit Hilbert space is used for quantum computations, then computational capacity is maximized, but coherent noise affects all states uniformly causing decoherence
Solution Approach 1:
The patent segments the full n-qubit Hilbert space into a protected code space and an error space. By selecting a specific stabilizer group, the code space is defined as the subspace invariant under the stabilizer operations. This segmentation allows the system to operate within a reduced subspace that is protected from coherent noise, achieving both computational capacity and coherence stability.
Solution Approach 2:
The patent applies local quality by creating a code space with specific local properties that make it immune to coherent noise. The stabilizer group is constructed such that the code space has enhanced local coherence properties, allowing certain qubits or subsystems to maintain their quantum states without affecting the overall computational capacity.
Data Source
AI summary
Technologies for addressing coherent noise in a quantum system are disclosed. To passively correct for errors in measurement caused by coherent noise, the quantum system implements an error correction code such that the error correction code effectively reduces the coherent noise to act as an identity operator in a protected subspace of a Hilbert vector space.