Patenting Quantum Computing Innovations – Part 2: Implementing a Pauli Z Gate

Patenting Quantum Computing Innovations – Part 2: Implementing a Pauli Z Gate By Sinan Utku Example 1: Implementing a Pauli Z Gate Quantum computing inventions come in a variety of forms. They include hardware and hardware-related inventions that are directed to components of a quantum computer or processes carried out by the hardware to carry out quantum computing processing. They also include software-related inventions that, e.g., implement a new quantum computing algorithm for achieving a useful end. Quantum computing inventions are often useful, contain a technological advance and in many cases include specific hardware components. However, as illustrated by the American Axle and Symantec cases, none of these properties are sufficient to confer patent eligibility. It is useful to consider specific types of quantum computing inventions to discuss typical patent eligibility issues that may arise. These inventions are based on well-known technologies that are discussed in most introductory quantum computing textbooks.[i] Consequently, none of them would satisfy the novelty or non-obviousness requirements for patentability. However, because they are well-known to many quantum computing practitioners, they are good vehicles for discussing and illustrating for such practitioners the patent eligibility requirement. Implementing a Pauli Z Gate As an example of an invention for implementing a quantum computing functionality, consider implementation of a Pauli Z-gate in a quantum dot-based quantum computer. This gate carries out the fundamental operation of flipping the phase of a qubit and is an important element in nearly all quantum computing processing. In a quantum dot-based qubit, its functionality can be implemented, for example, by causing a rotation of 𝜋 radians around the z-axis. To implement this, the hardware in the quantum computer could carry out the following: align the spin of the electron in the quantum dot along an initial direction to achieve a Hadamard basis |+> state; apply an external magnetic field at a right angle to the first direction for a time interval 𝛥t given by 𝛥t = 𝜋/w (where w is the Larmor frequency characterizing the external magnetic field); and flagging that the qubit has been placed in the Hadamard basis |-> state. Based on the Mayo/Alice framework, the eligibility of such an invention might be challenged based on the rationale that it recites a natural law, akin to the court’s finding in the American Axle case. In particular, an opponent, such as a patent examiner or adverse party in litigation, might argue that the invention is nothing more than the application of a natural law without any limitation to a particular method for achieving it. In particular, the opponent might argue that application of a magnetic field aligned perpendicular to the spin of an electron necessarily generates a rotation as a direct result of the applicable physical laws (similar to the facts in the American Axle case.) In response, the patentee could argue that the invention is specifically directed to implementing a Z-rotation in the context of a quantum dot that has been initially placed in a specific aligned state, and does not preempt all uses of applying a magnetic field to cause a Z-rotation. Including additional hardware details would likely help, such as those relating to the trapping of an electron in a quantum well that is implemented in a semiconductor substate. It is not clear that such arguments would prevail, as the patent examiner or court could find that these additional elements merely specify a general context in which the natural law is applied, and that granting a patent directed to such an invention might preempt all implementations of rotation of a state using a magnetic field in a quantum dot. However, inclusion of such underlying hardware details could increase the likelihood of surviving a patent eligibility challenge. [i] See, e.g., Peter Y. Lee, Huiwen Ji & Ran Cheng, Quantum Computing & Information: A Scaffolding Approach (1st ed. 2024); Daniel D. Stancil & Gregory T. Byrd, Principles of Superconducting Quantum Computers (2022); Thomas G. Wong, Introduction to Classical and Quantum Computing (2022); Michael A. Nielsen & Isaac L. Chuang, Quantum Computation and Quantum Information (10th anniversary ed. 2010); N. David Mermin, Quantum Computer Science: An Introduction (2007). Sinan Utku is a Special Counsel, Covington and Burling LLP; Instructor, Bilkent University Law School. Nothing in this article should be construed as reflecting the official views, opinions, or positions of any organisation or institution with which the author is affiliated. The author writes in a personal capacity only. September 17, 2026 Doug Finke2026-09-17T21:00:12-07:00 Leave A Comment Cancel replyComment Type in the text displayed above Δ This site uses Akismet to reduce spam. Learn how your comment data is processed.