Can quantum computers solve UK rail problems?
The Department for Transport and Network Rail are awarding millions - are they right?
You may have read on The Telegraph that the UK’s Department for Transport and Network Rail have awarded GBP 15 millions “to develop ‘quantum-optimised train schedules’” to “make Britain’s trains run on time”. The news piece made reference to two quantum start-ups, Q-CTRL, from Australia, and Oxford Quantum Circuits, from the UK. In fact the £15mn will be distributed across six different projects, selected among the most promising after an initial feasibility assessment. Other projects awarded by the the Government’s Quantum Catalyst Fund will tackle optimising energy grids (led by Phasecraft, a Uni. Bristol start-up), simulating actinide chemistry (led by Quantinuum), brain imaging (led by Cerca Magnetics, a Uni. Nottingham start-up), gravimetry for cartography (led by Delta g, based at Uni. Birmingham research park), and railway inertial navigation (led by MoniRail, a Uni. Birmingham spin-out).
On the face of it, £15mn seems a lot of money, but in fact the investment in any of the projects is pretty small. To put it in some context, UK trains serve about 1.5 - 1.7 billion passenger journeys each year, according to Office for Rail and Road statistics. If the 15 million had been awarded in full to the rail-improvement project, it would amount to 1 penny out of every journey; users could hardly expect a massive increase in service quality at that price. Therefore, UK rail passengers should not expect to see a great leap forward in service punctuality or efficiency following directly from this quantum computing project (I would be more optimistic regarding the quantum sensing projects, a technology that appears closer to bringing actual value).
To understand the ability of today’s quantum computers to perform useful calculations, it is useful to check the recent pre-print by a collaboration of quantum computing and cryptography experts (Scholte et al., “Assessing the benefits and risks of quantum computers”). Its figure 1 summarizes current best estimates for resources for a quantum computer to perform a useful calculation. We can read it as follows: typically, it will require at least 3-4 times more circuit ‘width’ and a 1000-fold improvement in number of T-gates compared to state-of-the-art. In short, useful calculations that can address some scientific or technical problem will be out of reach still for a few years still.
Why is the UK government awarding this money? First, getting a computer —quantum or otherwise— to solve any problem is not a simple task. These investments make sense as a way for experts —those developing quantum computing hardware and software on one side, and those currently solving those technical problems by other means on the other— to interact and learn from each other. The software solutions we use today to organize our rail services (or our energy grids, or thousands of other complex optimization problems) were not developed overnight, but it took decades of human ingenuity to have them. If we don’t want to spend a few more decades learning from scratch how to solve these important practical problems with quantum computers, the smart thing to do is to for experts to start now learning from each other, so that when quantum computers arrive, the technology is ready to hit the ground running and bring value swiftly. This is exactly what the Quantum Catalyst Fund competition aims to do, while supporting the thriving ecosystem of deep-tech start-ups spun out of UK universities.
Indeed, this is the second reason for the Quantum Catalyst Fund competition and, more generally, the Small Business Research Initiative: to support “quantum technologies in the UK across the broad spectrum of quantum computing, sensing, timing, imaging and communications” with a vision to transform the UK into a “quantum-enabled economy” by 2033. The UK has an unusually strong ecosystem of start-ups spanning the four quantum-tech pillars, much broader than what we can see in neighbouring France, Netherlands or Germany, thanks in part to ten years’ investments through the National Quantum Technologies Programme. Thus, these projects are also aimed at providing support to strong emerging start-ups spun-out of British universities at a time when venture capital is short and interest rates high, with a goal to strengthen them in what will be a very competitive next few years on the quantum technology arena.
It remains to be seen how effective the UK efforts will be in the international arena, where the US is investing increasingly strongly in quantum through its National Quantum Initiative, and Europe aims to become the world’s “quantum valley” through its 2030 Strategic Research and Industry Agenda 2030.