In a paper published in leading international science journal Nature today (15/11/07 UK time) the research team revealed a system that uses individual photons – single particles of light – as a ruler for microscopic distances.
The experiment was performed in the laboratory of Dr Geoff Pryde at Griffith University's Centre for Quantum Dynamics, by him and his PhD student Brendon Higgins. Centre Director, Professor Howard Wiseman, developed the theory, together with University of Sydney's Dr Stephen Bartlett and Macquarie University's Dr Dominic Berry.
Pryde’s apparatus used single photons, with each photon making a number of passes through the sample being measured.
Using just 36 photons making a total of 378 passes, the team was able to measure length differences less than one ten thousandth of the width of a human hair.
“This is an incredibly small amount of light.” said Pryde. “For comparison, scanning a barcode uses quadrillions of photons. Even the dim standby light on your DVD player shines out many trillions of photons a second.”
"Similar schemes based on interferometry – a technique using waves of electromagnetic radiation such as light – have been used for centuries to measure length, and other properties of objects, with great accuracy." said Wiseman.
"The key difference is we have done it in a way that gets as much information out of each pass of a photon through the sample as is allowed by Heisenberg's uncertainty principle. In this sense, it’s the best measurement possible – something that’s never been done before."
"The obvious applications are in making accurate measurements using less light than was previously thought possible. This is particularly important in fields such as medical research, as passing light through a biological sample can damage it," said Pryde.
So why do we need to measure with such accuracy"
"Measurement underpins all science, and through history we've seen that advances in precision measurement lead to unexpected scientific discoveries, which in turn lead to new technologies and applications," Pryde said.
"Old-style interferometers taught us that the Earth wasn’t moving through a mysterious substance called 'aether', but actually through a vacuum. This ultimately led to Einstein’s theory of relativity. We don’t know yet where this new technique will lead us.”
The team's next goal is to use more single photons and passes to get an even finer measurement.
"In principle this is possible, but there are some technological hurdles to overcome first!” said Pryde.
THE SCIENCE BEHIND THE DISCOVERY:
In the strange world of quantum physics, a photon can simultaneously take two different paths to the same destination. Where the photon goes next depends on the difference between the lengths of the two paths. If the length of one path is known, this allows scientists to measure the length of the other path with great accuracy. The novel feature of the Griffith experiment is to make the photon retrace the paths many times before detecting it. This amplifies the effect of the difference in path lengths. The same idea can also be applied to measuring other quantities like speed, frequency, and time.
The technique combined concepts from research in quantum computers (through Australia’s Centre for Quantum Computer Technology), in quantum control, and in quantum communication. “This is a great example of ideas coming together from different directions to make something new and exciting,” said Bartlett.
Jeannette Langan | EurekAlert!
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences