Nobel Prize for Physics – experts respond

The 2012 Nobel Prize in Physics has been awarded to Serge Haroche and David J. Winelan.

The Laureates independently invented and developed ground-breaking methods for measuring and manipulating individual particles while preserving their quantum-mechanical nature, in ways that were previously thought unattainable.

The official Nobel announcement and background on the award winning research can be found here.

Dr Simon Benjamin of Oxford University’s Department of Materials, said:

“There is worldwide race to learn how to control matter and energy at the quantum level. This is an immense challenge because quantum states are extremely delicate and difficult to manipulate, but when we achieve sufficient control we will be able to produce radically new kinds of technology. Applications range from communication systems through to ultra-accurate clocks and sensors and ultimately the realisation of the “universal quantum computer” which will be able to perform tasks impossible with any conventional supercomputer.

“Wineland and Haroche are two of the pioneers who have taken great steps toward getting the levels of control we need. Wineland’s expertise is in controlling individual atoms: he holds them in a vacuum by electromagnetic fields and then manipulates and measures them with lasers. Haroche’s work is in a sense the exact opposite – he has mastered the art of producing ‘cavities’ that trap photons, the particles of light, for long periods. He can then manipulate and probe the state of the photons using streams of atoms that pass through the cavity. Together these two researchers have massively advanced our abilities to control the interaction between matter and energy at the quantum level.”

Professor Charles Adams, Department of Physics, Durham University, said:

“This is very exciting! Schrodinger thought we had about as much chance of seeing individual atoms and single photons as we have of seeing a dinosaur. Haroche and Wineland showed that we can see and control single atoms and single photons, and what happens when they interact with the classical world, thereby addressing the famous Schrodinger’s cat paradox.

“Their work lays the foundation for 21st technologies where we begin to exploit the fundamental quantum nature of our world.”

Professor Patrick Gill, Senior NPL Fellow & Head, Optical Frequency Standards, National Physical Laboratory, said:

“What Dave W and Serge H have done is demonstrate near complete control over the quantum state of a particle (ion or atom), and develop ways of holding the particle and preparing it in a particular quantum state and watching It evolve over time in response to stimuli (eg pulses of laser light or microwave photons). The biggest problem is the very fragile nature of quantum states which “decohere” very quickly into eg a mixture of thermal states Due to environmental influences (eg temperature, noise due to electric and magnetic fields, collisions with other Particles). The first thing DW does is to electromagnetically trap and cool the ion down to near absolute zero temperature (-273 degrees C or 0 Kelvin) via laser cooling, which he first suggested along with another 3 laureates

“Dehmelt (for ions) and Hansch and Schawlow (for atoms) back in 1975. This cooling reaches an effective temperature of few micro-Kelvins above absolute zero. With this arrangement, the ion is in its ground state of quantised motion in the trap. Alternatively, SH uses a superconducting cavity arrangement at liquid helium temperatures below 1 K. Both then use tailored laser pulses or microwaves to prepare the particle in a particular quantum state and then manipulate it, and watch the results of this manipulation over relatively “long” times of order 1 sec before decay sets in. Then they can go back and do it again many times over. This is exciting because it allows physicists to watch and control the interface between the quantum world and the macroscopic world.

“Their results over nearly 4 decades have led the way in demonstrating how to control quantum states of particles, allowing fascinating insights to the questions raised by the eminent physicists back in the 1920s (Schrodinger, Einstein etc) eg the cat paradox, entanglement, quantum state teleportation, which were just thought experiments then. Equally, they have also demonstrated how to live with the quantum barrier that you hit when you go to smaller and smaller dimensions (cf Moore’s Law in the quest for evermore memory on computer chips). So we now have demonstrations of quantum computing architectures based on qubits rather than bits (ie super-positions of 1s and 0s instead of just 1 and 0. This gives potential huge increase in computing power

“For certain mathematical operations (eg determining prime numbers associated with large numbers), which has significance for security and finance codes based on such large numbers.

“Classical computers cannot do this on viable timescales, but a quantum computer with enough qubits (a few hundred) might.  So far, operations with 14 qubits have been demonstrated so there’s a way to go yet, but DW basically started the experimental demo of these ideas. On another tack, he has pioneered the development of optical atomic clocks based on cold trapped ions, which will likely replace the cold caesium atom fountain clock in some years’ time as the international standard of time. Recently he demonstrated his Al+ ion clock which is demonstrating uncertainty at a level between 1 and 2 orders of magnitude improvement over the Caesium standard. What’s more interesting is that this Al+ clock works uses quantum logic ideas based on his quantum computing research. The impact of this clock on fundamental physics has already been shown through its direct demonstration of special and general relativity effects in the lab. The clock is able to sense (via its frequency) changes in particle velocity and changes in is height position of 30 cm due to its changed gravitational potential.”

Professor Ian Walmsley, Chair of Experimental Physics at Oxford University, said:

“Both Haroche and Wineland have developed an amazing set of tools for exercising exquisite levels of control over individual atoms and light particles. Their work has given us a number of profound insights into the way the quantum world works.

“Wineland makes the world’s best clocks, giving us a definition of time based on quantum phenomena: atomic clocks are already essential for everything from the sat nav in your car to global communications systems. Wineland’s next generation ‘quantum clocks’ will be equally important.

“Haroche has shown how making measurements in quantum mechanics fundamentally alters the thing measured. In a beautiful series of experiments he has revealed the emergence of classical probability from the quantum world in real time.

“We are at the cusp between having a very deep experimental way of controlling and manipulating quantum phenomena and being able to use that control to enable radically new and different kinds of technologies.”

Dr Alexander Belton, Department of Mathematics and Statistics, Lancaster University, said:

“Professors Haroche and Wineland both work in the field of quantum optics. This is the part of physics concerned with the interaction between light and matter at the quantum level, so between individual particles of light, photons, and matter, such as atoms or ions (which are atoms but with electrons missing). Haroche and Wineland have been able to do experiments which involve manipulating individual particles while maintaining their quantum nature; this is very difficult to achieve because particles tend to interact with the environment and then behave in a classical (non-quantum) manner. Quantum optics may offer a route to implementing quantum computers, which some researchers believe will bring an advance in computing power far beyond what present systems offer.”

Professor Sir Peter Knight, a colleague in the same field as Serge Haroche and David Wineland, and President of the Institute of Physics, said:

“Haroche and Wineland have made tremendous advances in our understanding of quantum entanglement, with beautiful experiments to show how atomic systems can be manipulated to exhibit the most extraordinary coherence properties; Haroche working with cavity quantum electrodynamics and Wineland with trapped ions.

“Their work demonstrates very fundamental behaviour of quantum systems under complete control, and underpins quantum technologies relevant to quantum computing and atomic clocks.”

Prof Jim Al-Khalili, Professor of Physics, University of Surrey, said:

“Very exciting – this year’s Nobel Prize recognises some of the most incredible experimental tests of the weirder aspects of quantum mechanics. The two winners have for some years led teams in Boulder Colorado and in Paris that have carried out quite remarkable experiments that have demonstrated and confirmed phenomena such as quantum entanglement and decoherence. Until the last decade or two, some of these results were nothing more than ideas in science fiction or, at best, the wilder imaginations of quantum physicists. Wineland and Haroche and their teams have shown just how strange the quantum world really is and opened up the potential for new technologies undreamt of not so long ago.”