Hello, and welcome to the first 2022 edition of Lost in Space-Time, the physics newsletter that attempts to extract information about the fundamental nature of reality, and thereby inadvertently contributes to the heat-death of the universe. This month, we ask whether telling the time is also hastening the demise of all things, draw some (not very) historical parallels to rumours surrounding a possible new particle discovered at CERN, and sidestep the question of what researchers managing to put a tardigrade into a quantum-entangled state actually means.
Does telling the time speed the heat death of the universe?
As a roundabout way of addressing whether telling the time is hastening the end of all things – the subject of a great feature in the magazine last month, in case you missed it – let me first say that, for me, entropy is a great illustration of the misconceptions people have about how a lot of science works.
The way people think it works: through patient observation and brilliant insight, scientists uncover regularities in the workings of the world that allow them to develop laws of nature valid for all time. The way it actually works: through patient observation and brilliant insight, scientists uncover regularities in the workings of the world that allow them to develop laws of nature that they then constantly fudge as more data comes in to ensure that they’re still saying something useful.
Case study: entropy. When the laws of thermodynamics were first devised in the 19th century, entropy was all about heat engines: about temperature differences, the direction of heat flows, and the impossibility of converting all the energy put into a system into useful work through a combustion engine. That became formulated as a law, the second law of thermodynamics, that expressed all that as: this thing called entropy always increases.
Then along came James Clerk Maxwell, he of electromagnetism fame, with his thought experiment about a “demon” that could pick apart molecules travelling at different velocities (and therefore at different temperatures) and send them different ways through a trapdoor. Depending on the way the demon decided to do things, it could in theory reverse the normal direction of heat flow, causing entropy to decrease.
Super-accurate atomic clocks extract a lot of information from the universe Credit: Dorling Kindersley/UIG/SCIENCE PHOTO LIBRARY
It took a long time for us to realise that this wasn’t actually the case (even without a demon involved), but we eventually did with the Shannon theory of information in the mid-20th century. It’s because entropy can also be associated with information, quantifying the amount of information needed to specify what’s going on in a system. (Specifically, there is always an energy cost associated with erasing information.) Incorporate the entropy of information into the Maxwell demon picture, and you see that by gaining information about the system, the demon is increasing entropy. Et voila! The second law of thermodynamics is saved – by shifting the goalposts about what counts as entropy.
Just as an aside, “energy” is another example of such a conveniently plastic concept. It’s tempting to say that the conservation of energy – the mantra that energy can be neither created nor destroyed – is a law of nature. Well, it kind of is, in the sense that energy conservation is a foil for a very important apparent rule, that the laws of physics do not vary in time (if you want to get lost in those weeds, the key is Noether’s theorem, which you can read up about here).
But to translate that into a law of energy conservation, we’ve found ourselves constantly changing what counts as energy as new facts come in. Energy not conserved in relativistic nuclear reactions? Well darn it, make mass a form of energy that is “released” in those reactions, and then it still is!
Where was I? The point is that we might more accurately see these “effective” laws of nature as useful organising principles, because they effectively set boundaries on what is and isn’t possible in nature . So, it in fact makes sense to keep our definitions elastic to allow the “law” to hold.
Which brings me to the question: does telling the time increase entropy in the universe? Connections between time and entropy have long been floated, largely because entropy’s ineluctable increase seems to be the only thing that can explain why time only goes one way – forwards, not backwards. But making such connections explicit has always been hampered by our not really truly grasping what time itself is – for a start, it is treated completely differently in quantum physics, where it’s an independent variable that sits outside the theory (a clock ticking in the background, if you like), and in general relativity, where it’s a real and physical thing that is part of the fabric of reality, space-time.
As the feature explores , it could be that we’ve got things precisely backwards. If clocks, the means by which the passage of time can be measured, were themselves a third type of thermodynamic engine like heat engines and information processors that act to increase entropy, that might explain the connection between entropy increase and time’s flow – and a lot else about time itself, as well as putting a fundamental limit on how accurate clocks themselves can be. Well, are they a third type of thermodynamic engine? I’ll leave you to make up your own minds from the feature, but I’d say it’s a very definite maybe.
What is clocks?
Apologies to regular readers, but I can’t possibly pass up the opportunity given by that last item to link to my favourite five minutes of TV of all time, in which New Scientist consultant editor Stuart Clark attempts to answer that very question, what is clocks…?
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Every month in this newsletter, I’ve taken it upon myself to highlight a feature from New Scientist’s extensive archive that I find particularly interesting or relevant. You may have read the feature a couple of weeks ago in the magazine about the anomalies that are turning up in particle decays involving a particular heavy type of quark, the bottom or beauty quark, at the LHCb experiment at CERN.
These anomalies aren’t new, and I’ve already expressed my scepticism about the idea that they won’t disappear as more data comes in, both in this newsletter and elsewhere. But our feature is written by an LHCb physicist, Harry Cliff, and I’m prepared to run with the mounting excitement he expresses there, while being interested to read that theorists are firming up their ideas of what any new particle the anomalies are pointing to might be. Broadly, it could be something that starts to provide a more unified picture of the electroweak and the strong forces , currently described by two theories – quantum electrodynamics and quantum chromodynamics (QED and QCD to their friends) – somewhat inelegantly cobbled together to make the standard model of particle physics.
My archive pick for this month comes from 2016, and it explains why I still reserve my right to scepticism. Entitled “Bigger than the Higgs, bigger even than gravitational waves...” , it was about another unexplained effect cropping up at the LHC back then, and, as a particle physicist, I’d say it more than justified the hyperbole at the time. You couldn’t move at conferences for people talking about the “750 GeV anomaly”, a bump spotted by two LHC experiments, ATLAS and CMS, which pointed to the existence of a particle six times as massive as the Higgs boson, which weighs in at 126 gigaelectronvolts, or GeV, in particle physicists’ unconventional conventional mass units . Unlike the Higgs (and unlike gravitational waves), it wasn’t predicted by existing theories of physics. Well, more data came in – and within a few months the 750 GeV anomaly was dead again, confirmed as a mere statistical blip.
The two situations aren’t exactly analogous: whereas the 750 GeV bump pointed directly to the creation of a new particle with that mass, the LHCb anomalies are expressed in deviations from the expected decay rates of particles, which might indicate the indirect influence of a very heavy particle of as-yet undetermined mass. These deviations do now seem to be cropping up in multiple decay “channels ”, as particle physicists call them, and are at the very least persisting as new results come in, if not yet reaching the gold standard of statistical significance needed to claim a discovery. Perhaps do start holding your breath for that. I can guarantee that, for their own sakes as much as ours, those involved at LHCb will be working all hours of day and night to come to a more definitive answer.
How to quantum entangle a tardigrade
This is a story that is as cute as it is profound. (Hats off to my colleague Alex Wilkins, who spotted it while browsing papers on the arXiv physics preprint server). Scientists at Nanyang Technological University in Singapore have managed to put a tardigrade in an entangled state with a superconducting qubit.
Tardigrades are microscopic animals renowned for their ability to survive extreme conditions, even perhaps in interstellar space . This is just as well, because these latest experiments involved them enduring temperatures just 0.01 degrees above absolute zero. The tardigrades were definitely alive both before and after the supposed entanglement – but as to their status in between, no one can truly say. As team member Tomasz Paterek at the University of Gdańsk, Poland, told us: “You never know in this kind of experiment what exactly is the part of [the tardigrade] that takes part in the entanglement”.
Tardigrades are known to be hardy beasts CREDIT: Science Photo Library/Alamy
Just a quick heads-up for anyone in the vicinity of London or anyone who fancies making the trip there – covid situation permitting – on 26 March. I’ve been working with our fantastic events team to put together a one-day masterclass called “Frontiers of Cosmology” that will be held at the British Library. It will feature a series of six talks from top UK-based researchers on topics from the true nature of the big bang, to the hunt for dark matter and energy, to the search for quantum theories of gravity – plus I’ll be hosting a panel discussion with all six speakers at the end of the day where you get to put your own questions to them. You can find more details on the topics to be covered by following the link above.
1. While I’m busy blowing my own trumpet, do check out my interview with philosopher of consciousness and reality David Chalmers in the magazine issue currently in the shops (dated 29 January). He’s a mind-blowing person to talk to, and you can make your own mind up whether you agree with his contention that virtual worlds are just as real as the real world (not least because the real world is itself highly likely to be virtual…).
3. The omicron wave of covid-19 means our award-winning festival of science, New Scientist Live, has been rescheduled to begin on Saturday 12 March. For those who want to turn up in person, the venue is Manchester, UK– but if you can’t make it physically, you can be there virtually, because this time all the talks will be streamed live.
That’s it for now. Thank you for reading! If you have any comments or questions, you can let me know by emailing me at lostinspacetime@newscientist.com and I’ll try to answer them in an upcoming newsletter. If you know someone who might enjoy Lost in Space-Time, please forward it on. If you haven’t yet, you can sign up to get it in your inbox every week here.
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