(The following article by our very own Phil Merchant originally appeared on the Dead Cat Live Cat blog, and is being shared here with thanks to Dead Cat Live Cat.)

Quantum hardware is rapidly progressing, and innovators are finding success in securing patent protection for their developments. Alongside this progress, inventors are also investing their efforts in the software that quantum computers will run. In this article, we consider what considerations and practice must patent applicants consider when seeking patent protection for their quantum algorithms.

Quantum computing promises to unlock the potential of quantum phenomena on real-word hardware to achieve significant increases in processing speed. Some research groups are already claiming to have achieved "quantum supremacy" – meaning a quantum device has performed a calculation that no classical computer can solve in a feasible amount of time. Large corporations, start-ups and research groups are making significant strides in developing new hardware to physically realise a large-scale quantum computer. As recently reported by the EPO, patent applications toward quantum computers have shown a significant increase in the last decade.

However, innovation is not limited toward the physical hardware. The principles of quantum mechanics that underlie the functionality of a quantum computer opens up new possibilities for new types of software. Quantum algorithms take advantage of the power of the quantum computer to deliver new solutions to real-world problems – optimisation, simulation and many other forms of data processing.

While inventors can be confident that patent protection is available for their quantum hardware, can they be similarly reassured that they can protect their novel quantum software? After all, those familiar with UK patent law may be aware that the UK Intellectual Property Office will examine additional requirements for software inventions, and not every algorithm is patentable. Do quantum computers fall within the already-developed approach to software patent examination?

UK Law on software inventions

Patent examination in the UK will assess a patent application for an invention for various criteria, including whether the invention is novel (i.e. the invention is new over what's already known) and inventive step (i.e. the new invention is nevertheless not obvious over what's already known). For software inventions, however, the UK patent office may also carefully assess an additional criterion – whether an "invention" is present in the first place. This is because the UK patents act specifically identifies computer programs as an example what is not to be considered an invention.

However, the UK patent office does regularly grant patents toward software inventions, even with the presence of the exclusion. This is the case because the UK Patents Act also states that the exclusion only applies if a patent claim relates to a computer program as such – i.e. the claim relates to a computer program and nothing more.

In assessing whether a claim relates to nothing more than a computer program, the patent office will consider the overall context of the software invention and its purpose and overall effect. If it can be determined whether the computer program has a contribution to the state of the art that is technical in nature, then it will not be excluded. As an example, simply reciting lines of code in a patent claim will likely lead to the claim being excluded, but establishing that code as more precisely controlling the navigation of an unmanned aerial vehicle may be sufficient to establish a technical contribution.

When considering the likelihood of patentability of a software claim, much importance is therefore placed on what the software will do when run, and whether that can be considered 'technical'.

Applying the law to quantum algorithms

The UK courts have not yet issued any judgements focusing on the applicability of the current practice to specifically quantum algorithms, but there is no reason to suspect that they would consider the existing practice as inappropriate.

First, the term "program for a computer" is broad enough to cover both classical and quantum algorithms. Second, the above test for 'technical contribution' is not solely applied to computer programs – it is applied to every category of "excluded matter" defined by the statute. This includes schemes, rules or methods for doing business or performing a mental act, scientific theories, and mathematical methods. While quantum algorithms are distinct from classical algorithms (by virtue of the more advanced technology that executes the algorithm) they find their basis in different mathematical methods and leveraging the rules of physics. Anything that extends the quantum algorithm beyond that of a classical algorithm is unlikely to be considered prima facie technical under the UK law.

Furthermore, the UK patent office has been very willing to apply existing practice to other, cutting-edge algorithms. For example, the UK patent office considers Artificial Intelligence programs to be another example of "program for a computer" and/or "mathematical method".

Until a decision from a UK court establishes to the contrary, patent applicants would be advised to apply the existing practice for classical algorithms to their new, quantum algorithms.

Assessing the technical contribution of quantum algorithms

The UK Patents Act does not define what is meant by "technical", nor can a definition be found in the associated case law. Indeed, whether or not a piece of software has a technical contribution can be a contentious point of disagreement between an inventor and the patent office (or the court).

Nevertheless, some guidance can be found by considering past decisions of the UK courts, including some "signposts" that may indicate the presence of a technical contribution for a computer program claim. These signposts are:

i) Whether the claimed technical effect has a technical effect on a process which is carried on outside the computer.
ii) Whether the claimed technical effect operates at the level of the architecture of the computer; that is to say whether the effect is produced irrespective of the data being processed or the applications being run.
iii) Whether the claimed technical effect results in the computer being made to operate in a new way.
iv) Whether the program makes the computer a better computer in the sense of running more efficiently and effectively as a computer, or whether there is an increase in speed or reliability of the computer.
v) Whether the perceived problem is overcome by the claimed invention as opposed to merely being circumvented.

The signposts are non-exhaustive, but provide useful guidance on common reasons for a computer program being considered technical. Signpost (i), for example, may be fulfilled if the computer program controls the operation of an external system such as a car-braking system. As a further example, a computer program that, when run, stores and loads data into/from a memory faster or more efficiently may fulfil signpost (iv).

Whether or not these signposts are valid for quantum algorithms is again untested by the courts, but it is likely that they are just as applicable. Each of the signposts are directed toward the general term "computer", which is not necessarily limited to the computer being a classical computer. Signpost (i), for example, assesses the effect of the program outside the computer, which is just as applicable to classical computers as quantum computers. Similarly, signpost (ii) discusses "architecture", which can be interpreted to cover both classical bits and qubits. Further, it is worth noting that the specific pieces of case law that that led to the development of the signposts are arguably just as relevant to quantum algorithms as to classical algorithms.

Again, until guidance is provided a UK court decision, a sensible approach is to consider the guidelines and existing assessment of technical contribution (including the use of the signposts) to be applicable to quantum algorithms.

Position of the UK patent office

The above assessment does appear to be consistent with the current approach being taken by UK patent examiners. For example, the applicability of the present test for software inventions to quantum algorithms was explicitly considered by the hearing officer in O/130/22:

"There was some discussion at the hearing as to whether a different approach should be taken for quantum computers as opposed to classical computers in relation to the signposts. I have reflected upon this and have reached the conclusion that the signposts are valid for quantum computers as for classical computers and still provide useful signposts as to whether the claimed invention makes a technical contribution. I will not go through the case law in detail which Lewison LJ considered when developing the signposts, but that case law is equally relevant to quantum computers as it is to classical computers.

Furthermore, given the level of abstraction of 'computer programs' as described and claimed in patents, it is important to consider whether or not the claimed invention, or rather its contribution, relates to the instructions which are provided to the computer, in its broadest sense, in order to direct how it operates. If the contribution does relate solely to such instructions, the question to then be determined is whether those instructions result in some form of contribution which is something more than a computer program as such, and I do not believe that the fact that a computer is a quantum computer or has a quantum element makes any meaningful difference to that deliberation""
[Reasons 43 – 44]

Conclusions

Given the above, what does the current approach of UK law mean for programmers of quantum algorithms seeking to obtain patent protection for their inventions?

First, some reassurance can be taken that patent protection is available for software inventions in quantum technology. Software patents are regularly applied for, and the UK patent office regularly reaches a positive assessment on technical contribution and, consequently, patentability.

Second, innovators would be advised to heed the current practice guidance as formulated for classical algorithms. In particular, when considering patent protection, thought should be given to what technical contribution the quantum algorithm may make, and to emphasise this contribution when drafting a patent specification. It is recommended that particular attention should be paid to the example 'signposts' given above; while these are not exhaustive examples of a technical contribution, explaining within your specification how at least one of these signposts is fulfilled can prove persuasive and increase chances of a grant.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.