One of the greatest pleasures of being a patent attorney in private practice, as well as one of the hardest challenges, is the constant exposure to new technologies. Every month, and sometimes every week, we need to take a deep dive into a technical area that is new to us and learn it well enough to write a coherent patent application about it. (I have heard it said that a patent attorney is someone who can write 40 pages about something he does not understand at all.) It can be both a blessing and a curse that the inventors who guide us on these journeys are leaders in their fields, and the new concepts that we struggle to grasp are second nature to them.
Nowhere have I had this feeling more acutely than in writing patent applications on quantum computing. Those of us who have studied a little quantum mechanics know that there is nothing about it that can be grasped easily by our physical intuition. The paradox of Schrodinger’s cat exemplifies this problem. In this famous thought experiment, the principles of quantum mechanics are extended to a cat in a closed box, who can be both alive and dead at the same time with a certain probability. Only when the box is opened does the “state” of the cat collapse to one of the two possibilities.
Quantum entanglement is even more bewildering: According to quantum theory, the states of two particles can be entangled even when the particles are distant from one another, and the entangled particles can exchange information with one another instantly, faster than the speed of light. Einstein considered such entanglement to be physically impossible. He referred to it as “spooky action at a distance” and argued that there must be something missing in the theory. In fact, experiments have shown quantum entanglement to be a reality, and it is one of the cornerstones of quantum computing. When I am working on a patent application in quantum computing and feel confused, I reassure myself that greater minds than mine have found the principles hard to grasp.
Theoreticians started to formulate the principles of quantum computing 40 years ago, but practical implementation still faces enormous challenges. Semiconductor technology has developed over this same period to make digital computers based on silicon chips cheap, reliable, and fantastically powerful, but what about quantum computers? They are still laboratory tools, far from commercial realization. Our clients are working on a number of different approaches, including arrays of atomic ions, trapped in a vacuum; superconducting current loops, known as “transmons”; and solid-state devices based on crystal lattice defects.
Perhaps the most difficult challenge standing in the way of practical quantum computing is decoherence – loss of information from a qubit (the quantum equivalent of a bit), which arises mainly from interaction with the environment. When a bit is stored in a digital memory, we can be confident that the value of the bit will remain unchanged over days and even years. Qubits, on the other hand, lose information within times ranging from nanoseconds to milliseconds. Quantum computations must be completed before the qubits decohere. One of our clients has invented a way to maintain coherence of a qubit over tens of milliseconds, which is long enough for his device to be called a “quantum memory.” Another is developing special techniques for quantum error correction, which can increase the fidelity of quantum computations even when the qubits start to decohere.
The past five years have seen a flurry of patents on hardware and software for quantum computing, including hundreds of patents by technology giants including Intel, IBM, Microsoft, and Google. Investors have taken interest, and quantum computing start-ups are proliferating. For patent attorneys, quantum computing is a great example of a field in which we have to deal with ideas that are abstract, but we do not need to argue with examiners about whether our claims are drawn to abstract ideas. When will we see the first lawsuit for infringement of a quantum computing patent? It is still anyone’s guess.