Griffith’s Professor Geoff Pryde, who led the project, says that such processes could be simulated using a “quantum hard drive”, much smaller than the memory required for conventional simulations.

“Stephen Hawking once stated that the 21st century is the ‘century of complexity’, as many of today’s most pressing problems, such as understanding climate change or designing transportation system, involve huge networks of interacting components,” he says.

“Their simulation is thus immensely challenging, requiring storage of unprecedented amounts of data. What our experiments demonstrate is a solution may come from quantum theory, by encoding this data into a quantum system, such as the quantum states of light.”

Einstein once said that “God does not play dice with the universe,” voicing his disdain with the idea that quantum particles contain intrinsic randomness.

“But theoretical studies showed that this intrinsic randomness is just the right ingredient needed to reduce the memory cost for modelling partially random statistics,” says Dr Mile Gu, a member of the team who developed the initial theory.

In contrast with the usual binary storage system - the zeroes and ones of bits - quantum bits can be simultaneously 0 and 1, a phenomenon known as quantum superposition.

The researchers, in their paper published in Science Advances, say this freedom allows quantum computers to store many different states of the system being simulated in different superpositions, using less memory overall than in a classical computer.

The team constructed a proof-of-principle quantum simulator using a photon - a single particle of light - interacting with another photon.

They measured the memory requirements of this simulator, and compared it with the fundamental memory requirements of a classical simulator, when used to simulate specified partly random processes.

The data showed that the quantum system could complete the task with much less information stored than the classical computer- a factor of 20 improvements at the best point.

“Although the system was very small - even the ordinary simulation required only a single bit of memory - it proved that quantum advantages can be achieved,” Pryde says.

“Theoretically, large improvements can also be realized for much more complex simulations, and one of the goals of this research program is to advance the demonstrations to more complex problems.”

Griffith University

The first observational evidence that the universe could be a hologram has been published in the journal Physical Review Letters.  The international study may lead to new beliefs on the Big Bang Theory and on quantum gravity, one of theoretical physics’ most profound problems.

Researchers from the University of Waterloo, Perimeter Institute for Theoretical Physics, University of Southampton (UK), INFN, Lecce (Italy) and the University of Salento (Italy), believe the study further explains how space and time emerged.

“We are proposing using this holographic universe, which is a very different model of the Big Bang than the popularly accepted one that relies on gravity and inflation,” said Niayesh Afshordi, professor of physics and astronomy at the University of Waterloo and Perimeter Institute, and lead author in the study.

“Each of these models makes distinct predictions that we can test as we refine our data and improve our theoretical understanding – all within the next five years.”

Theoretical physicists and astrophysicists first identified the concept of a holographic universe in the 1990s. Today, researchers have published observational evidence to support a 2D holographic explanation of the universe.

This work could lead to a functioning theory of quantum gravity, a theory that harmonizes quantum mechanics with Einstein’s theory of gravity.

“The key to understanding quantum gravity is understanding field theory in one lower dimension,” said Afshordi. “Holography is like a Rosetta Stone, translating between known theories of quantum fields without gravity and the uncharted territory of quantum gravity itself.”

Holography, with its more simplified approach, allows the researchers to study the dense conditions of quantum gravity during the Big Bang at its boundary, which provides as much information as studying the Big Bang itself.

From Planck Data to Planck Era: Observational Tests of Holographic Cosmology
Niayesh Afshordi, Claudio Corianò, Luigi Delle Rose, Elizabeth Gould, and Kostas Skenderis
Phys. Rev. Lett. 118, 041301 – Published 27 January 2017
DOI: 10.1103/PhysRevLett.118.041301

University of Waterloo

Read more news on http://www.nanotechnologyworld.org/news

With these results, the researchers from the field of ultrafast phenomena and photonics build on their earlier findings, published in October 2015 in the scientific journal Science, where they have demonstrated direct detection of signals from pure nothingness. This essential scientific progress might make it possible to solve problems that physicists have grappled with for a long time, ranging from a deeper understanding of the quantum nature of radiation to research on attractive material properties such as high-temperature superconductivity. The new results are published on 19 January 2017 in the current online issue of the scientific journal Nature: DOI: 10.1038/nature21024.

A world-leading optical measurement technique, developed by Alfred Leitenstorfer’s team, made this fundamental insight possible. A special laser system generates ultrashort light pulses that last only a few femtoseconds and are thus shorter than half a cycle of light in the investigated spectral range. One femtosecond corresponds to the millionth of a billionth of a second. The extreme sensitivity of the method enables 

detection of electromagnetic fluctuations even in the absence of intensity, that is, in complete darkness. Theoretically, the existence of these “vacuum fluctuations” follows from Heisenberg’s Uncertainty Principle. Alfred Leitenstorfer and his team succeeded in directly observing these fluctuations for the first time and in the mid-infrared frequency range, where even conventional approaches to quantum physics have not worked previously.

The conceptual novelty of the experiments is that instead of the frequency-domain techniques used so far, the physicists from Konstanz accessed quantum statistics of light directly in the time domain. At a chosen point in time, electric field amplitudes are directly measured instead of analysing light in a narrow frequency band. Studying different points in time results in characteristic noise patterns that allow for detailed conclusions about the temporal quantum state of light. As the laser pulse propagates together with the quantum field under study, the Konstanz physicists can, so to speak, bring time to a stop. Ultimately, space and time, that is “space-time”, behave absolutely equivalently in these experiments - an indication of the inherently relativistic nature of electromagnetic radiation.

As the new measurement technique neither has to absorb the photons to be measured nor amplify them, it is possible to directly detect the electromagnetic background noise of the vacuum and thus also the controlled deviations from this ground state, created by the researchers. “We can analyse quantum states without changing them in the first approximation”, says Alfred Leitenstorfer. The high stability of the Konstanz technology is an important factor for the quantum measurements, as the background noise of their ultrashort laser pulses is extremely low.

By manipulating the vacuum with strongly focused femtosecond pulses, the researchers come up with a new strategy to generate “squeezed light”, a highly nonclassical state of a radiation field. The speed of light in a certain segment of space-time is deliberately changed with an intense pulse of the femtosecond laser. This local modulation of the velocity of propagation “squeezes” the vacuum field, which is tantamount to a redistribution of vacuum fluctuations. Alfred Leitenstorfer compares this mechanism of quantum physics graphically with a traffic jam on the motorway: from a certain point on, some cars are going slower. As a result, traffic congestion sets in behind these cars, while the traffic density will decrease in front of that point. That means: when fluctuation amplitudes decrease in one place, they increase in another.

While the fluctuation amplitudes positively deviate from the vacuum noise at temporally increasing speed of light, a slowing down results in an astonishing phenomenon: the level of measured noise is lower than in the vacuum state - that is, the ground state of empty space.

The simple illustration with the traffic on a motorway, however, quickly reaches its limits: in contrast to this “classical physics” picture, where the number of cars remains constant, the noise amplitudes change completely differently with increasing acceleration and deceleration of space-time. In case of a moderate “squeezing”, the noise pattern is distributed around the vacuum level fairly symmetrically. With increasing intensity, however, the decrease inevitably saturates toward zero. The excess noise that is accumulated a few femtoseconds later, in contrast, increases non-linearly - a direct consequence of the Uncertainty Principle’s character as an algebraic product. This phenomenon can be equated with the generation of a highly nonclassical state of the light field, in which, for example, always two photons emerge simultaneously in the same volume of space and time.

The experiment conducted in Konstanz raises numerous new questions and promises exciting studies to come. Next, the physicists aim at understanding the fundamental limits of their sensitive detection method which leaves the quantum state seemingly intact. In principle, every experimental analysis of a quantum system would ultimately perturb its state. Currently, still a high number of individual measurements needs to be performed in order to obtain a result: 20 million repetitions per second. The physicists can not yet say with certainty whether it is a so-called “weak measurement” in conventional terms of quantum theory.

The new experimental approach to quantum electrodynamics is only the third method to study the quantum state of light. Now fundamental questions arise: What exactly is the quantum character of light? What actually is a photon? Concerning the last question, that much is clear to the Konstanz physicists: instead of a quantized packet of energy it is rather a measure for the local quantum statistics of electromagnetic fields in space-time.

Original publication: C. Riek, P. Sulzer, M. Seeger, A.S. Moskalenko, G. Burkard, D.V. Seletskiy, A. Leitenstorfer: “Subcycle Quantum Electrodynamics”. Nature, Advance online publication. DOI: 10.1038/nature21024

University of Konstanz 

“We at TiNT aim to inspire a sense of child-like wonder and curiosity in our listeners as we delve into the beautiful world of nanoscience, using music and imagination. We talk to passionate scientists, explain cutting edge research and innovation and, most of all, encourage you to understand the world in a whole new way.”

We have also put up a new page with information about the hosts of the show and the best way to contact us and bring articles and news items to our attention.

See you in February….

The TiNT Team

Today in Nanotech is a new podcast beginning in February 2011 featuring all things Nanotechnology. We will be meeting with world-class nanotechnology researchers and talking about cutting edge science on a monthly basis.

You have obviously already found the blog (episodes will be posted here as soon as they become available!) but you can also follow us on twitter: TiNanotech or contact us via email todayinnanotech@gmail.com

Send us links to researchers, topics and papers you would like to hear discussed, or if you would like to feature as a participant on the show - and come back and get the first Episode in 2011!

Today in Nanotech is a new podcast beginning in February 2011 featuring all things Nanotechnology. We will be meeting with world-class nanotechnology researchers and talking about cutting edge science on a monthly basis.

You have obviously already found the blog (episodes will be posted here as soon as they become available!) but you can also follow us on twitter: TiNanotech or contact us via email todayinnanotech@gmail.com

Send us links to researchers, topics and papers you would like to hear discussed, or if you would like to feature as a participant on the show - and come back and get the first Episode in 2011!

See on Scoop.it - Nanotechnology News

Chemists discover a way to take carbon dioxide from the air and make carbon nanofibres, a valuable manufacturing material.