A new model for quantum noise

June 18, 2014
A new model for quantum noise

The National Physical Laboratory (NPL) has published research in Nature Communications that updates one of the most fundamental concepts in the physics of quantum electronic devices - the standard tunnelling model (STM).

The STM was introduced in the 1970s to describe the thermal properties of glass at temperatures close to absolute zero. At these low temperatures quantum mechanics takes over from and strange properties begin to emerge. Quantum tunnelling is one such property and describes how atoms can cross barriers that they should not be able to according to classical physics.

The performance of many is hampered by a type of low frequency noise known as 1/f noise, or flicker noise. This is thought to be caused by two-level states, quantum systems where an atom, for example, can exist in exactly two states simultaneously. The STM predicts that, as temperatures decrease, this noise should also decrease and eventually vanish completely.

New measurements made in this research, over longer time scales than previously possible, contradict this prediction, showing an increase in noise at low temperatures. The measurements were made possible by implementing an ultra-stable frequency-tracking technique used in atomic clocks and by producing a superconducting resonator insensitive to fluctuations in temperature.

The measurement results suggest that the STM model fails at the extremely and low powers that devices for and detecting single particles are operating at.

To account for these results, NPL scientists and their collaborators are proposing a new model, which includes significant interactions between two-level systems. The interactions lead to spectral diffusion which alters the properties of the resonator. As well as explaining the measurement results from this work, the also explains results of other recent studies concerning qubits (quantum bits), the building blocks of quantum computing.

Cutting-edge quantum technologies in areas such as computing, communications, navigation, timing and information security require incredibly sensitive measurements in order to develop into commercial applications. NPL continues to work to advance these measurements and carry out the fundamental science to underpin them.

Explore further: Researchers find nondestructive method to study quantum wave systems

More information: "Evidence for interacting two-level systems from the 1/f noise of a superconducting resonator." J. Burnett, et al. Nature Communications 5, Article number: 4119 DOI: 10.1038/ncomms5119. Received 14 November 2013 Accepted 14 May 2014 Published 17 June 2014

Related Stories

Tricking the uncertainty principle

May 15, 2014

(Phys.org) —Caltech researchers have found a way to make measurements that go beyond the limits imposed by quantum physics.

Heat control in nanoscale SQUIDs

January 28, 2014

Nanoscale Superconducting QUantum Interference Devices (nanoSQUIDs) are potentially the most sensitive measurement devices in the world. They detect changes in an electromagnetic property known as magnetic flux, which means ...

Progress in the fight against quantum dissipation

April 16, 2014

(Phys.org) —Scientists at Yale have confirmed a 50-year-old, previously untested theoretical prediction in physics and improved the energy storage time of a quantum switch by several orders of magnitude. They report their ...

Supercomputing for materials simulation

May 9, 2014

The National Physical Laboratory (NPL) and international partners are using advanced supercomputers to develop a new framework for accurate materials simulation.

Recommended for you

First-ever X-ray image capture of material defect process

January 17, 2017

From blacksmiths forging iron to artisans blowing glass, humans have for centuries been changing the properties of materials to build better tools – from iron horseshoes and swords to glass jars and medicine vials.

Flexible ferroelectrics bring two material worlds together

January 17, 2017

Until recently, "flexible ferroelectrics" could have been thought of as the same type of oxymoronic phrase. However, thanks to a new discovery by the U.S. Department of Energy's (DOE) Argonne National Laboratory in collaboration ...

Theory lends transparency to how glass breaks

January 16, 2017

Over time, when a metallic glass is put under stress, its atoms will shift, slide and ultimately form bands that leave the material more prone to breaking. Rice University scientists have developed new computational methods ...

Self-assembling particles brighten future of LED lighting

January 16, 2017

Just when lighting aficionados were in a dark place, LEDs came to the rescue. Over the past decade, LED technologies—short for light-emitting diode—have swept the lighting industry by offering features such as durability, ...

A novel way to put flame retardant in a lithium ion battery

January 16, 2017

(Phys.org)—A team of researchers at Stanford University has found a novel way to introduce flame retardant into a lithium ion battery to prevent fires from occurring. In their paper published in the journal Science Advances, ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

NoTennisNow
not rated yet Jun 18, 2014
STM stands for scanning tunneling microscope, not standard ...
swordsman
not rated yet Jun 19, 2014
The measurement itself can produce noise. Classical analysis can show this.
George_Rajna
Jun 19, 2014
This comment has been removed by a moderator.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.