gshc2020.com

• F1: Back at Base is an IMG Production for the BBC, hosted by Rosamund Pike
• Co-hosts & Executive Producers are Sarah Holt and Holly Samos
• The Producers are Alasdair Cresswell, Joe Aldridge, Jack Winstanley and Mitchell Marshall
• Production Management from Abbie Collingwood, Katie Killeen and Giulia Duggan
• The Senior Producer is Ollie Kneen
• The Executive Producer for IMG is Steve Tebb
• The Story Editor and Scriptwriter is Sarah Holt
• The Showrunner is Holly Samos
• And the Commissioning Editor at the BBC is Stevie Middleton
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"There are also repeat offenders - countries and clubs where things are not improving and they have demonstrated that they are not capable of hosting games in acceptable conditions.

"France, Spain, Portugal and Italy are major tourist destinations that are very used to hosting people from all over the world, but clearly treat football fans completely differently - like a threat or second-tier citizen."

Security arrangements and policing strategies for European matches are developed via a combination of host clubs, national governments, local authorities and regional police forces, with input from Uefa, who run the competitions.

The way fans are treated can vary drastically based on the place they are visiting, the policies of those running the country and/or city, the behaviour of home fans, and the context of the game. Plus, not every fan will have the same experience as others on the same trip.

"There are some things that are small humiliations - being forced to enter a stadium four hours before kick off, put on a bus for hours with no toilet, having lip balm taken off you," Evain said.

"These things are rarely necessary, and are either a way for the police to exert a form of social control, or just completely outdated.

"Then we see things like pushing thousands of fans through gates no bigger than an apartment door - there are clearly policing strategies and infrastructural failures that are putting people's lives at risk.

"It just takes a few people to panic for things to go really wrong."

BBC Sport asked fans who are experienced European away travellers to document how English clubs' trips unfolded during the last two Champions League and Europa League matchweeks, choosing a range of games in different places with varied approaches to policing and security measures.

Gemma Manns, 44, Chelsea fan in Naples, Italy: "We avoided arriving in Naples until the afternoon of the game, based on Napoli fans' reputation for hostility.

"Hearing about the two young guys who were stabbed was horrible but not surprising.

"In the end we didn't see any trouble around the ground once we got to Naples, and the checks were all efficient.

"We were kept behind for over an hour after the game, and big groups of ultras stayed in their stand to try to intimidate us, so we felt at risk.

"Once we headed towards the designated buses after leaving the ground, the police completely disappeared, and we were packed on.

"The doors were open doors and we had no protection when it felt like we might need it - that was really sketchy."

Jude Aston, 21, Aston Villa fan in Istanbul, Turkey: "I am a wheelchair user, and although we were warned by Villa about what conditions would be like, it was still worse than I expected.

"Once we were in the ground, us disabled supporters had to sit inside a cage in front of the away end. It had thick bars and some wiring that meant I could hardly see any of the goal at the end of the pitch in front of me.

"The cage was locked for most of the match, and I was the furthest one along - I couldn't get out to use the toilet until half time and I don't know what I would have done if there was a fire or something. I felt quite claustrophobic. It was unsettling.

"My personal assistant was separated from me, outside the cage, and I was worried about my phone dying in an emergency because I wasn't allowed to take a power bank in.

"I know in theory the cage is for our safety from home fans, getting to and from the stadium was efficient, and the police and stewards were very friendly, but it's 2026 - there has to be a better way than this."

Jane Boland, 61, Liverpool fan in Marseille, France: "The riot police made entering and exiting the stadium really hard work. After being told to arrive at a designated meeting point more than four hours before kick off, we were held in overcrowded areas and made to wait for ages, sometimes with difficult or no toilet access.

"Leaving the stadium took over two hours after full time - by far the longest I've ever experienced. We were stood packed on stairwells for what felt like forever, and I had awful back pain afterwards. I understand that someone passed out and needed medical attention, and in retrospect I'm surprised it was only one.

"After two days of everything being great and nothing but friendly interaction between the two sets of fans, we were treated like cattle.

"I probably spent about £1000 on the trip, most of that in Marseille itself, so it smarts to be treated so badly as a 'customer'."

Sue Fox, 68, Spurs fan in Frankfurt, Germany: "Transport was pretty efficient, overall. The meeting point was well organised and the police gave clear instructions.

"Then we took a train and they marched us through a very dark, muddy forest for about half an hour. When we arrived at the ground the gates were locked so we had to queue for an hour, and we were all packed very close together. It was uncomfortable and inappropriate.

"The men were able to go to the toilet in the bushes, but what were we supposed to do? It was nearly two hours without being able to go.

"Inside, the only women's toilet was in the home end, so we had to use the one there, which felt wrong and had the potential to be unsafe."

Dylan White, 21, Arsenal fan in Milan, Italy: "On the way to the stadium we had to wait in big, tight queues for the designated metro for a long time, and then got packed on like sardines.

"Outside the ground, some extremely thorough ticket checks meant we were in very tight queues again, which got tighter and tighter because the entry gates were locked until 20 minutes before kick off.

"Finally they let us through and we had to walk up the enormous spirals to enter the ground, just about making it in time for kick off.

"We were out of the San Siro within about half an hour of full time, which we'd have definitely taken, and then people had to go and collect their portable chargers which had been confiscated on the way in.

"The police were brilliant with us but the way of getting fans to and then into the ground could do with a lot of work."

Luke Stanley, 22, Man City fan in Bodo, Norway: "The whole experience in and around the stadium was very straightforward and everyone was very friendly - entry was as easy as it could have possibly been.

"We hardly saw any police officers and the ones we did were helpful guiding us.

"There were only three toilets in the away end, and there wasn't much food available to buy, but overall treatment was very good."

Supporters commonly told the BBC that issues with organisation and the authorities occurred more often than risks posed by rival fans.

So why is a downward spiral in standards seemingly happening?

"The political atmosphere at the moment in Europe doesn't really help when it comes to police accountability," Evain says.

"We see a number of governments wanting to show muscle, and football fans are an easy target.

"The British clubs are often in a better position compared to fans from other countries because there are very good UK police delegations who travel with fans to away matches, and the clubs are well organised with pre-match security visits and bring a high number of their own staff."

The final report into the 2022 fiasco, commissioned by Uefa and compiled by a panel of independent experts, found Uefa primarily at fault and made a series of recommendations to improve fan safety at matches, including Uefa taking more responsibility for security in their role as the event organiser.

"I am deeply concerned by the lack of tangible reforms since our report," says Clifford Stott, professor of social psychology at Keele University and one of the authors of the report.

"Uefa's response to our findings was limited to formal statements, with no substantive follow-ups or evidence of implemented changes.

"The safety and security of future events remain at risk."

Illustration by Eleanor Shakespeare %!s()

In quantum physics, every object, such as an electron, is matched to a mathematical formula called the wave function. The wave function encodes all the details of an object’s quantum state, which means physicists can predict what an object might do in an experiment by combining its wave function with other equations.

But if we accept that the whole world is quantum – and many researchers do – then much larger objects ought to have wave functions, including the whole universe. This is a point of view that was previously argued by, for instance, physics luminaries like Stephen Hawking.

Now, however, Eddy Keming Chen at the University of California, San Diego, and Roderich Tumulka at the University of Tübingen in Germany have shown that complete knowledge of this universal wave function may be fundamentally inaccessible.

“The wave function of the universe is like a cosmic secret that physics itself conspires to keep. We can know enormously much about how the universe behaves, yet remain fundamentally uncertain of which quantum state it is in,” says Chen.

Previous studies posited the universal wave function’s form based on theoretical models of the cosmos and didn’t directly address what role experiments and observations could play in determining its details. Chen and Tumulka started with a more pragmatic question: given some set of wave functions that could reasonably represent our universe, could observations enable researchers to pick out the correct one?

The pair started with mathematical results from quantum statistical mechanics, which studies properties of collections of quantum states. Another ingredient in their calculations was the fact that the universal wave function would require a very large number of parameters, or exist in an abstract state with many dimensions.

Strikingly, upon completing the calculations, the team had to conclude that the universal quantum state is essentially unknowable.

“Any measurement that’s allowed according to the rules of quantum mechanics will give us very limited information about the wave function of the universe. It’s impossible to determine the wave function of the universe with any useful accuracy,” says Tumulka.

JB Manchak at the University of California, Irvine, says this work helps us better understand the limitation of our very best empirical methods and already has some counterparts in general relativity – Albert Einstein’s theory of gravity. At the same time, this may not be surprising, as quantum theory was never conceived as a theory for cosmically large scales, he says.

“The wave function, of a small system or of the entire universe, is a rather theoretical entity. Wave functions are relevant, not because we see them but because we use them,” says Sheldon Goldstein at Rutgers University in New Jersey. He says that this means it may not be a problem that we are unable to choose a single most accurate universal wave function from a narrow set of candidates, because any of the wave functions in the set may have a similar effect when used in further calculations.

Chen says that he and Tumulka now want to connect their work to large systems that are smaller than the whole universe, and especially to investigations into techniques like “shadow tomography”, which are used to determine such system’s quantum states. But the work’s philosophical implications matter as well. Specifically, researchers should take it as a note of caution to not overly rely on positivist thinking, or the notion that a statement is meaningless or unscientific if it cannot be tested experimentally, says Tumulka. “Certain things actually exist out there in reality, but we cannot measure them,” he says.

This reasoning may also play into the century-long debate on how to make sense of quantum mechanics itself, says Emily Adlam at Chapman University in California. In her view, the new result can be seen as motivation to put more stock into interpretations of quantum equations, such as the wave function, that emphasise relationships between quantum objects and each observer’s perspective rather than positing one objective view of reality codified by a single mathematical object. %!s()

Physics, it is fair to say, hasn’t gone to plan. After decades of hopeful searching, dark matter still hasn’t been directly detected. We found the Higgs boson, but nothing to pave the way forward. And string theory, that much-touted theory of everything, has yet to yield a clear, testable prediction. Confidence is low. Where do we go from here?

In recent years, many physicist-authors of popular science have sidestepped that question. Where once they pointed boldly to the next great discovery, they are now often seen retreating into philosophical reflection or re-explaining what we know already. Not so Antony Valentini at Imperial College London. In Beyond the Quantum: A quest for the origin and hidden meaning of quantum mechanics, he presents something almost antiquated in its rarity: a big idea.

As the title suggests, his central target is quantum mechanics, which has underpinned physics for a century. This hinges on the wave function, a mathematical expression that can, so the textbooks say, specify the full state of any system, from a fundamental particle to a cat or even you and me.

The strange thing about the wave function is that it doesn’t usually describe ordinary, localised objects at all, but rather spread-out, fuzzy, wave-like versions of things. Never mind. When we look at an object – again, so the textbooks say – the wave function “collapses” into a familiar yet random outcome, with a probability given by the Born rule (named after physicist Max Born). Only now do we have an object with definite properties in a definite place.

Much as mainstream physics tries to ignore it, the interpretation of the wave function has always been a mystery – and there are essentially only two realistic answers. One is that the wave function really does describe reality – that electrons, cats and people genuinely exist in many states at once, spread out across space and possibility. This is the many-worlds interpretation, with its vast metaphysical implications.

Pilot-wave theory has long been known to reproduce all the predictions of quantum mechanics

The other answer is that the wave function isn’t the whole story. The dominant theory here, much developed by Valentini, is pilot-wave theory, first proposed by theorist Louis de Broglie in 1927 and later revived by physicist David Bohm.

Pilot-wave theory takes the wave function to be real but incomplete. It suggests that it acts as a guiding structure for individual particles, rather like waves steering plastic bottles floating on the sea. The particles themselves are never spread out or indeterminate – their wave-like behaviour comes from the pilot wave and where they sit on it.

Pilot-wave theory has long been known to reproduce all the predictions of quantum mechanics, with no fundamental randomness. But, as Valentini stresses, this agreement rests on an assumption: that particles are in equilibrium with the wave, distributed in just the right way. That assumption fits today’s experimental data – the results are practically undeniable – but it need not always have held.

Valentini proposes that, in the early universe, particles were distributed far from quantum equilibrium, before “relaxing” into their present state, rather as a cup of coffee cools to match its surroundings. In this view, the Born rule and its randomness are no longer basic features of nature, but historical accidents – they are by-products of cosmology.

That striking payoff isn’t the only one. Quantum randomness also prevents any practical exploitations of non-locality, the immediate interaction of objects separated by time and space. If the Born rule didn’t hold in the early universe, Valentini argues, instantaneous communication across vast distances would have been possible, perhaps leaving subtle imprints in the cosmic microwave background. If any relics from this era still exist, such superluminal signalling might be achievable now.

Given the lack of evidence, this might sound a bit wild were it not for Valentini’s meticulous analysis of how orthodox quantum mechanics came to hold sway (the book is worth reading for this alone). If there is one weakness, it is the lack of a plain description of the pilot wave. Still, whether or not it proves to be true, Valentini’s work at least shows us that, in a field short on confidence, this is what a genuinely big idea looks like.

Jon Cartwright is a writer based in Bristol, UK %!s()