How we see is an intriguing question - especially for quantum physics. Photo: Mark Mainz/Getty Images
Show Hide image

What does it mean to see something? Take a look at Schrödinger’s cat

It takes only a few photons to trigger our visual sense. Tantalisingly, a few photons can exist in superposition.

What does it mean to see something? It’s a surprisingly philosophical question, especially where quantum physics is concerned.

Quantum physics describes the world at the level of single atoms and smaller, looking at things such as photons, particles of light. These objects are able to be in two places at once, or to spin clockwise and anticlockwise at the same time, a phenomenon known as superposition. Something happens to stop bigger stuff being in two places at once, even though it is composed of atoms and molecules that can exhibit superposition. In experiments, we have achieved superpositions of molecules composed of about 800 atoms but these collapse very quickly. Something about increasing size (or weight) seems to stop the weirdness in its tracks.

Intriguingly, our eyes may help to unravel this. At a meeting of the American Physical Society in Columbus, Ohio, researchers reported that our eyes can register things at the level where quantum weirdness remains. It takes only a few photons to trigger our visual sense. Tantalisingly, a few photons can exist in superposition. The next step is to see whether we notice anything weird when photons in superposition enter our eyes.

This is ambitious. Our unconscious perception is important even to establish whether we see a few photons. The experiments reported in Ohio put subjects in a blacked-out room. When photons were flashed at their eyes, they had to say whether the flash came from their left or their right. Because of the low light intensity, few of the flashes were registered consciously: the subjects couldn’t remember seeing the flash but had to report their gut instinct. They got it right enough of the time to suggest that their brains had registered the photons.

Conscious perception has long been of interest to those who study quantum physics because observation can disturb quantum weirdness. Fire a photon at a double aperture and it will go into a superposition and pass through both apertures simultaneously – but only if no one is looking. Put a detector on the apparatus and the superposition disappears. This is the source of Erwin Schrödinger’s well-known thought experiment. He conceived a situation in which quantum physics leaves a cat both dead and alive, as long as no one observes it.

What is particularly interesting about real-world experiments is that the detector’s presence seems to determine whether the photon behaves like a wave or a particle. It does not require that a person consciously register the result. There is a mystery here about the nature of observation and measurement and what effect it has on the way the microscopic world manifests in our experiments.

No one understands how an atom or photon “knows” that it is – or might be – being tracked. That is what makes the new proposal so exciting. If you cut out the detection apparatus and go straight to the human eye, a slew of questions and opportunities arises. Does a future collision with the molecular apparatus of the retina count as a detection? Is there a difference between human and electronic photon detection? Does it make a difference whether we are conscious or unconscious of the photon’s arrival?

We may have to wait a couple of years for answers. These experiments are beyond our present capabilities, but our horizons are expanding. They promise insight into issues that have been bothering quantum philosophers for a century.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 19 June 2015 issue of the New Statesman, Mini Mao

Getty
Show Hide image

So much for "the table never lies" – data unravels football's biggest lie of all

London side Brentford FC are using data to rethink the usual football club model.

It’s a miserable day for practice, the rain spitting down on the manicured training pitches of Brentford Football Club. Inside a tiny office marked Director of Football, Rasmus Ankersen is waiting for his phone to ring. The winter transfer window closes in 11 hours and there are deals to finalise.

Ankersen, a 33-year-old Dane with a trim beard and hair pulled into a small ponytail, seems relaxed. Perhaps he knows that the £12m transfer of the striker Scott Hogan to Aston Villa is as good as done. Or maybe his comfort comes from Brentford’s performance this season. The small west London club sits safely in the top half of the second tier of English football – at least according to management’s own version of the league table, which is based on “deserved” rather than actual results. Officially, on 31 January, when we meet, the team is 15th of 24.

“There’s a concept in football that the table never lies,” says Ankersen, whose own playing career was ended by a knee injury in his teens. “Well, that’s the biggest lie in football. Your league position is not the best metric to evaluate success.”

Brentford are an outlier in English football. Since the professional gambler Matthew Benham bought a majority share in 2012, they have relied on the scientific application of statistics – the “moneyball” technique pioneered in baseball – when assessing performance.

The early results were positive. In 2014, Brentford were promoted from League One to the Championship and the next season finished fifth. That same year, Benham’s other team, FC Midtjylland, which is run on similar principles, won the Danish Superliga for the first time.

Yet in 2016 Brentford slipped to ninth. Despite the disappointing season so far, Ankersen insists the strategy is the right one for “a small club with a small budget”.

Underpinning Brentford’s approach is the understanding that luck often plays a big part in football. “It is a low-scoring sport, so random events can have a big impact,” Ankersen says. “The ball can take a deflection, the referee can make a mistake. The best team wins less often than in other sports.”

In a match, or even over a season, a team can score fewer or more than its performance merits. A famous example is Newcastle in 2012, says Ankersen, who besides his football job is an entrepreneur and author. In his recent book, Hunger in Paradise, he notes that after Newcastle finished fifth in the Premier League, their manager, Alan Pardew, was rewarded with an eight-year extension of his contract.

If the club’s owners had looked more closely at the data, they would have realised the team was not nearly as good as it seemed. Newcastle’s goal difference – goals scored minus goals conceded – was only +5, compared to +25 and +19 for the teams immediately above and below them. Statistically, a club with Newcastle’s goal difference should have earned ten points fewer than it did.

Moreover, its shot differential (how many shots on goal a team makes compared to its opponents) was negative and the sixth worst in the league. That its players converted such a high percentage of their shots into goals was remarkable – and unsustainable.

The next season, Newcastle finished 16th in the Premier League. The team was not worse: its performance had regressed to the mean. “Success can turn luck into genius,” Ankersen says. “You have to treat success with the same degree of scepticism as failure.”

Brentford’s key performance metric is “expected goals” for and against the team, based on the quality and quantity of chances created during a match. This may give a result that differs from the actual score, and is used to build the alternative league table that the management says is a more reliable predictor of results.

Besides data, Brentford are rethinking the usual football club model in other ways. Most league clubs run academies to identify local players aged nine to 16. But Ankersen says that this system favours the richer clubs, which can pick off the best players coached by smaller teams.

Last summer, Brentford shut their academy. Instead, they now operate a “B team” for players aged 17 to 20. They aim to recruit footballers “hungry for a second chance” after being rejected by other clubs, and EU players who see the Championship as a stepping stone to the Premier League.

It’s a fascinating experiment, and whether Brentford will achieve their goal of reaching the Premier League in the near future is uncertain. But on the day we met, Ankersen’s conviction that his team’s fortunes would turn was not misplaced. That evening, Brentford beat Aston Villa 3-0, and moved up to 13th place in the table. Closer to the mean.

Xan Rice is Features Editor at the New Statesman.

This article first appeared in the 16 February 2017 issue of the New Statesman, The New Times