Vlatko Vedral, The Oxford Physicist Who Put a Number on Entanglement

Vlatko Vedral is Professor of Quantum Information Science at the University of Oxford, a Serbian-born physicist who has spent three decades asking what entanglement is and what it can do. Entanglement is the link that lets two particles share one quantum state. As a PhD student in London he helped find a way to put a number on it, and that idea made his name.

His curiosity has since carried him from magnets and heat to birds, bacteria and a tardigrade. With his colleague Chiara Marletto he proposed a tabletop test of whether gravity itself is quantum, which may be the biggest open question in physics. He is also a warm and witty explainer. He has written seven books, three of them for general readers, and he writes a lively Substack.

Chess with his grandfather and a teacher called Euclid

Vlatko Vedral was born and grew up in Serbia, and the Observer described him in 2010 as originally from Belgrade. His grandfather taught him chess when he was four, and Vedral jokes that his game has hardly improved in all the decades since, so he is happy to call himself a weak player.

The teacher who shaped him most taught mathematical logic at his high school. The pupils called him Euclid. His real name was Mihailo Veljković, and Vedral remembers a short, bearded man who would solve an Olympiad puzzle several different ways while the class struggled to find even one. They were in awe of him. Yet he was, in Vedral’s words, “an exceptionally kind and gentle human being and a truly great pedagogue”.

Not every subject won him over. He found history dull and chemistry baffling, since its pictures of electrons as overlapping bubbles seemed like made-up rules. Deeper ideas were already calling, though. As a high school student he read The Ghost in the Atom, a book of interviews by Paul Davies with leading quantum physicists. There he first met the idea that growing entanglement might give time its direction.

Chemistry finally made sense when he learned quantum physics properly at Imperial, and the subject he had once disliked became, in his words, amazing. He now says that all chemical bonds come down to entanglement between the electrons that atoms share. So the bubbles were entanglement all along.

Three bottles of champagne at Imperial

Vlatko Vedral took a first-class degree in physics at Imperial between 1992 and 1995, specialising in theory. He stayed on for a PhD on the quantum theory of entanglement, with Peter Knight as his supervisor, and finished it in March 1998.

He entered the field at an exciting moment. Peter Shor had just shown that a quantum computer could split huge numbers into their factors, the very maths that protects much of today’s online shopping and banking. Vedral’s very first paper, with Adriano Barenco and Artur Ekert, drew up the full quantum circuit for Shor’s method, right down to the steps for adding and multiplying.

The celebration came in 1997, with his first paper in Physical Review Letters. It was the group’s first in that journal for ten years, and Knight bought three bottles of champagne to toast it. Many more papers followed.

Putting a number on entanglement, the fuel of quantum technology

The 1997 paper that made his name, Quantifying Entanglement, was written with Martin Plenio, M. A. Rippin and Knight. It asked a plain question. How much entanglement does a pair of particles hold? The authors first set out the rules that any fair measure must obey, and then they built a whole family of measures that pass every one of those tests.

The idea is easy to picture. Imagine a map of every state two particles can share, with the unentangled states forming a country in the middle. An entangled state sits somewhere outside the border, and the amount of entanglement it holds is simply how far it lies from the nearest point inside. A state far from the border is strongly entangled.

The ruler they chose comes from information theory, and the result is called the relative entropy of entanglement. In 1998 Vedral and Plenio showed that it sets a ceiling on how many perfect entangled pairs two distant partners can distil from a supply of noisy ones. He later gathered much of his thesis into a long review in 2002.

Why does that matter outside a physics department? Quantum computers and many kinds of quantum-secured communication run on entanglement, and they use it up as they work, much as a car burns fuel. A way to measure it tells engineers how much of that resource a device really holds, and Vlatko Vedral says the method he introduced in his PhD has since become widespread.

He also showed that entanglement is not the whole story. A 2001 paper he wrote with a colleague split the links between two systems into a classical part and a quantum part. What is left is now called quantum discord. It can exist with no entanglement at all, and a later review credits the idea jointly to that paper and to Ollivier and Zurek, who named it the same year.

From Merton College to Leeds, Singapore and Oxford

After the PhD his career moved quickly. He spent part of 1998 as a research fellow in Oxford, and then two years as a junior research fellow at Merton College. He then returned to Imperial as a lecturer in 2000, taught at Keble College in Oxford on the side, and was made a Reader in 2003.

Leeds came next, and in October 2004 it made him its Centenary Professor of Quantum Information. He held the chair until 2009. From December 2007 he also ran a second group in Singapore, at the Centre for Quantum Technologies, along with a physics chair at the National University there.

He came to Oxford in June 2009 and is a fellow of Wolfson College. Vlatko Vedral’s website jokes that ever since, he has been “in an entangled state of professorship” there.

The honours followed the work. He won a Royal Society Wolfson Research Merit Award in 2007, became a Fellow of the Institute of Physics in 2017 and joined the Academia Europaea in 2020. Also in 2017, Clarivate named him a highly cited researcher, one of the physicists whose work others cite most. His reply was warm and modest. “I am really surprised and delighted that the quantum community appreciates my work,” he said.

Forty doctoral students and a wide circle of friends

Much of his influence has travelled through people, and by his own count in 2020 forty students had completed a PhD with him. At Oxford he also led a group of fifteen academics working on quantum technology inspired by biology. It was based at the James Martin School.

He writes about his friends and co-workers with real warmth. Saro Fazio is “my friend”. The lab physicists Marco Genovese, Fabrizio Piacentini and Ettore Bernardi are his “Italian buddies”, and he calls them wizards. Many of his best-known recent papers are with Chiara Marletto, who did her PhD at Oxford, and together they have worked on gravity, time and the laws of physics.

His co-authors run from his own doctoral students to some of the best-known names in physics. They include Roger Penrose, Anton Zeilinger and David Deutsch.

Entanglement turns up in everyday magnets

Entanglement was long seen as a delicate quirk of microscopic objects. By 2008 Vedral could write in Nature that physicists now see it as common and hardy, and much of the road there ran through magnets.

In 2001 he and two colleagues studied a chain of magnetic atoms and found that turning up the heat or the magnetic field could sometimes raise the entanglement rather than destroy it. That was a real surprise.

The next step was to spot entanglement without taking a material apart. In 2005 he and his colleagues showed that an everyday reading, how strongly a material responds to a magnet, can act as a witness that entanglement is present. A year later, with Časlav Brukner and Anton Zeilinger, he applied the test to measurements of copper nitrate made in 1963. The old data could not be explained without entanglement.

In 2008 he and three colleagues wrote a long survey. It shows how entanglement changes as a material goes through the quantum cousins of water turning to ice. That matters for real machines. A quantum computer is a big object with many parts that act on each other, and engineers need to know how entanglement behaves as they build bigger ones.

Wolfson College sums it up well. It says his main contribution is measuring entanglement and applying it to large systems, “such as, for example, cats”.

Heat and energy in the tiniest machines

Heat is another thread. In 2009 he, Koji Maruyama and Franco Nori wrote a review of Maxwell’s demon, the imaginary imp that seems to cheat the laws of heat by sorting fast molecules from slow ones.

Two years later came a result in Nature with four colleagues. Wiping a computer memory normally costs energy and warms the surroundings. The team showed that if whoever does the wiping is entangled with the memory, the wipe can instead release energy and cool things down, using up the entanglement as it goes.

In 2020 he and David Felce designed a quantum fridge whose two cooling steps happen in no fixed order, a purely quantum trick that no ordinary fridge could pull off. Two years later another team built a version using nuclear spins.

The stakes are practical. Every chip gives off heat as it works, and the smaller devices become, the more quantum rules decide how efficient they can be and how much energy they waste. His Oxford group says its work on heat and quantum physics could help find the limits of energy efficiency in future technologies.

Looking for quantum effects in birds, bacteria and a tardigrade

Some of his boldest work asks whether life itself uses quantum physics. In a 2011 study, he and four colleagues looked at the built-in compass that lets some birds feel the Earth’s magnetic field.

Using the leading model of how the compass works, they found that its superposition and entanglement last at least tens of millionths of a second in the living bird. That beats the best similar molecules that chemists have made in the lab.

Later work went further. A 2018 paper with Marletto and two others modelled live sulphur bacteria tightly coupled to light, and in that model the bacteria and the light were entangled.

In 2021 he joined a team that linked a tardigrade, a tiny animal famous for surviving almost anything, to a superconducting qubit, a quantum bit made from a chilled circuit. The animal spent 420 hours at under a hundredth of a degree above absolute zero. Then it woke up.

Why does this matter? If living things use quantum effects, that would change how we understand senses like the bird’s compass, and even the everyday chemistry that keeps living things going. It could also point engineers to nature’s own tricks for protecting delicate quantum states, which is the aim of quantum technology inspired by biology.

Offering advice at the constructor theory table, and a new look at time

Constructor theory, developed by David Deutsch and Chiara Marletto, restates the laws of physics as rules about which tasks are possible and which are not in our universe. Vedral describes his own part with humour. He compares himself to a spectator at a chess game who keeps offering the players advice that nobody asked for.

The advice has turned into real science. In 2018 the three of them proposed a new version of the gravity test. A 2022 experiment with single photons, run with a team that included Marco Genovese, showed how one-way change fits laws that work the same forwards and backwards in time. In June 2026 they published a review of the main experiments that could test the theory.

Time fascinates him as well. In a 2017 paper he and Marletto argued that time can emerge from entanglement between a clock and the rest of the universe. In 2021 they and their colleagues showed that ordinary quantum change can be rebuilt as a chain of teleportations in time, and photon experiments in the same paper agreed with the idea. Early in 2026 he spoke about it at the Institute of Physics in London.

Seven books that bring quantum ideas to everyone

His first four books were for students, and each grew out of teaching. Modern Foundations of Quantum Optics came out in 2005. Introduction to Quantum Information Science followed a year later, and it began as lecture courses he had been asked to give in several countries.

Introductory Quantum Physics and Relativity came in 2010. He wrote it with Jacob Dunningham, and it is based on the courses the two of them taught to students at Leeds. Solid State Quantum Information, with Wonmin Son, followed in 2011.

Decoding Reality, From Micro to Macro and Portals to a New Reality

Decoding Reality came out in 2010 and again in 2018. It was his first book for general readers, and it argues that information, not particles, is the basic building block of everything in the universe. He told the Observer that information is “the only concept capable of almost explaining itself”. Asked whether information was just another word for God, he turned the question round. “I’d like to explain the origin of God,” he said.

From Micro to Macro followed in 2018. It asks whether every science might one day come down to physics, walking from the quantum world through chemistry and biology to economics.

Portals to a New Reality is his newest book. It came out in October 2025 from Allen Lane and Basic Books, and it argues that physics stands where it stood just before Planck, Einstein and Bohr changed everything. It then names five experiments that could open the way to new laws, and one involves entangling a human with Schrödinger’s cat.

Leading physicists welcomed it warmly. David Deutsch called him “a revolutionary in the best sense”, and Artur Ekert, his co-author on that very first paper, called the book “a bold manifesto for those who believe real progress begins with asking better questions”. Paul Davies, whose book of interviews he had read at school, wrote that he could think of no better person to rethink physics through a quantum lens.

Vlatko Vedral says he always writes with his sixteen-year-old self in mind. He wants the next generation of physicists to be more adventurous than his own. He has even proposed teaching quantum physics from kindergarten, since young children have not yet built up the habits that make it feel strange to adults.

He keeps the conversation going on his Substack, Musings on Quantum Mechanics, where recent essays run from entanglement in living things to the nature of the mind. He also gives talks at venues such as the Royal Institution in London.

Guitar, wakeboards and a telescope pointed at Saturn

Away from physics, Vlatko Vedral draws, goes wakeboarding and plays electric guitar with the Marshall amp, he says, turned all the way up to 11. He is a rock fan at heart. One essay wonders whether a rainbow, scaled down into sound, would ring out like the chords that open Chuck Berry’s Johnny B. Goode. He prefers to think that God, just like him, is particularly fond of rock and roll.

For one birthday he was given a telescope. The first thing he did was point it at Saturn from a balcony in a small village in Piedmont, and he was thrilled to see the rings. Moments like that, he wrote, are exactly why he loves physics, because it “magnificently uncovers a surprising unity in what would otherwise appear to be a chaotic universe”.

His favourite Oxford pub, he has written, is the Royal Oak. He enjoys a joke as well, and admits that his children would call some of his jokes dad jokes.

Testing whether gravity is quantum, one of the biggest questions in physics

The question now most linked to his name is one of the biggest in physics. Our two best theories, quantum mechanics and Einstein’s general relativity, have never been joined, and nobody has yet shown whether gravity follows quantum rules like everything else. Gravity is so weak that this is hard to test.

In 2017 Vedral and Marletto proposed a way to find out on a tabletop, by putting two small masses each in a superposition of two places at once. The masses then feel only each other’s gravity. If they end up entangled, they argued, gravity must itself be quantum, because a classical field acting locally could not link them that way.

Sougato Bose and his colleagues published a sister proposal in the same issue. The idea is now known as the Bose-Marletto-Vedral experiment, after all three. In 2025 a large team, with Vedral and Roger Penrose among its authors, wrote a white paper that sets out how to build it with tiny diamonds.

The experiment has not been done yet, and physicists are still debating exactly what a positive result would prove, which is part of what makes it such a lively problem. Vedral is happy to say where he stands. “My bets are that the masses would entangle in an actual experiment,” he wrote in 2023. “Anyway, time will tell,” he added.

An anti-gravity machine, with a quantum twist

In February 2026 he, Marletto and Pablo Saldanha proposed a second test with a playful twist. A single mass placed in two positions at once, and measured in a special way, could push a nearby matter wave away. Classical gravity only ever attracts. So seeing that push, they argue, would show that gravity is quantum.

Vedral called it an anti-gravity machine. The experiment is hard, but he is betting on his Italian friends. “My bet is on them to do it by 2030,” he wrote. Settling the question would tell us whether gravity plays by the same rules as everything else in nature, from black holes to the birth of the universe.

Falling atoms kept to Einstein’s rule in 2026

His gravity work reached the laboratory in 2026. On 3 September Oxford reported a study in Science Advances led from Ben-Gurion University of the Negev, the University of Ulm and Oxford, with Vedral and Penrose among the authors. The team split each rubidium atom’s quantum wave into two paths on a chip. One path was held still against gravity and the other was left to fall freely, and then the two were brought back together.

The result matched Einstein’s equivalence principle, the rule that anyone in free fall feels no gravity, applied to a quantum wave. It does not show that gravity itself is quantum. What it does show is that quantum physics keeps working when it is pushed into gravity’s territory, and for Vedral that is the point.

We have no consistent theory telling us why quantum physics should fail. This experiment pushes quantum mechanics into one of its most intriguing frontiers, gravity, and shows that, once again, its predictions hold.

Vlatko Vedral, quoted in a University of Oxford Department of Physics news release, 3 September 2026

That optimism runs through everything he does. Back in 2010 he told the Observer that scientists have always proved wrong anyone who gives up on a problem because it “looks too complicated”. “That’s why I believe there is hope for us to understand more and more,” he said.

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