How Quantum Computers Use Special Devices to Control Qubits
This patent describes a way for quantum computers to control special quantum bits, called topological qubits, using a "partial interferometric device" to perform specific operations.
Original patent title: “Quantum computers having partial interferometric quantum gates”
This patent describes a way for quantum computers to control special quantum bits, called topological qubits, using a "partial interferometric device" to perform specific operations. Granted to Microsoft Technology Licensing in 2016 with 23 claims and 12 forward citations, and it is expected to expire in 2033.
Coverage
What does this patent actually cover?
This patent describes a quantum computer design that uses a "partial interferometric device" to perform operations on "topological qubits" (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1, 10, 16). This device can generate single qubit gates, like a "θ/2 phase gate" (Claim 2, 4), or "entangling gates" for multiple qubits (Claim 5). The core idea is to position specific "target quasiparticles" of the qubit within a central region of the interferometric device (Claim 3, 11). For example, a quantum computer could use a "Fabry-Pérot double point contact interferometer" (Claim 12) to apply a "π/8 phase gate" to a topological qubit made of "Majorana zero mode quasiparticles" (Claim 7, 8, 20).
The gap
What does this patent NOT cover?
- Does not cover quantum operations that do not use a "partial interferometric device" as described.
- Does not cover quantum computers that only use non-topological qubits.
- Does not cover qubits formed from quasiparticles other than "Ising-type" or "Majorana zero mode" quasiparticles.
- Does not cover quantum gates that are not "phase gates" or "qubit operators" applied by the partial interferometric device.
- Does not cover interferometric devices that are not "partial" or do not include a "Fabry-Pérot double point contact interferometer."
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The clever bit is using a "partial interferometric device," specifically a "Fabry-Pérot double point contact interferometer," to precisely manipulate "topological qubits." This allows for the application of specific quantum operations, like phase gates, in a way that can complement "topologically protected quantum gates" within a larger quantum computer architecture, offering a path to more robust quantum computation.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Microsoft's research into topological quantum computing
Experimental setups for Majorana zero mode detection
Quantum computing architectures exploring fault tolerance
Devices using 5/2 Quantum Hall systems or topological superconductors
Why it matters
The bigger picture
This patent is significant for the field of topological quantum computing, a promising approach to building quantum computers that are inherently more resistant to errors. By describing specific mechanisms for controlling topological qubits using "partial interferometric devices," it contributes to the foundational technology needed to build fault-tolerant quantum computers. This area of research aims to overcome a major hurdle in quantum computing: the fragility of qubits.
Filed
December 16, 2013
Granted
February 9, 2016
Market context
Who's building on this
Companies in this space
Microsoft Technology Licensing LLC, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a primary driver in topological quantum computing research, with significant investments in this area. Other major players in quantum computing, such as IBM, Google, and academic institutions, are also exploring various qubit architectures and control mechanisms, though their specific approaches may differ.
Market impact
This patent contributes to the foundational intellectual property for topological quantum computing, a field that seeks to build inherently fault-tolerant quantum computers. While commercial products based directly on this specific technology are still in early development, the patent helps define the landscape for future quantum hardware, potentially enabling a new class of robust quantum processors that could revolutionize industries from medicine to materials science.
Claim 1 — Plain English
What this patent covers
This patent describes a quantum computer design that uses a "partial interferometric device" to perform operations on "topological qubits" (Claim 1, 10, 16). This device can generate single qubit gates, like a "θ/2 phase gate" (Claim 2, 4), or "entangling gates" for multiple qubits (Claim 5). The core idea is to position specific "target quasiparticles" of the qubit within a central region of the interferometric device (Claim 3, 11). For example, a quantum computer could use a "Fabry-Pérot double point contact interferometer" (Claim 12) to apply a "π/8 phase gate" to a topological qubit made of "Majorana zero mode quasiparticles" (Claim 7, 8, 20).
The clever bit
The clever bit is using a "partial interferometric device," specifically a "Fabry-Pérot double point contact interferometer," to precisely manipulate "topological qubits." This allows for the application of specific quantum operations, like phase gates, in a way that can complement "topologically protected quantum gates" within a larger quantum computer architecture, offering a path to more robust quantum computation.
What it does not cover
- Does not cover quantum operations that do not use a "partial interferometric device" as described.
- Does not cover quantum computers that only use non-topological qubits.
- Does not cover qubits formed from quasiparticles other than "Ising-type" or "Majorana zero mode" quasiparticles.
- Does not cover quantum gates that are not "phase gates" or "qubit operators" applied by the partial interferometric device.
- Does not cover interferometric devices that are not "partial" or do not include a "Fabry-Pérot double point contact interferometer."
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Strong
Citation count
22/40
Moderately cited
Claim breadth
15/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
5/20
Granted 10–20 years ago
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$100K – $319K
Midpoint $200K · 7.4 yr remaining · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
23 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Bonderson, P., & Freedman, M. H. (2016). How Quantum Computers Use Special Devices to Control Qubits (U.S. Patent No. 9,256,834). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/9256834/quantum-computers-having-partial-interferometric-quantum-gates
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Quantum Computers Use Special Devices to Control Qubits cover?
This patent describes a way for quantum computers to control special quantum bits, called topological qubits, using a "partial interferometric device" to perform specific operations.
Who owns patent US 9256834?
Microsoft Technology Licensing owns this patent, granted in 2016.
When does this patent expire?
This patent is expected to expire on December 16, 2033, when the invention enters the public domain.
What is patent US 9256834 cited by?
This patent has been cited by 12 later patents that build on its ideas.
What problem does this patent solve?
This patent is significant for the field of topological quantum computing, a promising approach to building quantum computers that are inherently more resistant to errors. By describing specific mechanisms for controlling topological qubits using "partial interferometric devices," it contributes to the foundational technology needed to build fault-tolerant quantum computers. This area of research aims to overcome a major hurdle in quantum computing: the fragility of qubits.
What does this patent NOT cover?
Does not cover quantum operations that do not use a "partial interferometric device" as described.
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