Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum memory with record-breaking capacity based on laser-cooled atoms

18.12.2017

The emerging domain of parallelized quantum information processing opens up new possibilities for precise measurements, communication and imaging. Precise control of multiple stored photons allows efficient handling of this subtle information in large amounts. In the Quantum Memories Laboratory at Faculty of Physics, University of Warsaw a group of laser-cooled atoms has been used as a memory which can store simultaneously up to 665 quantum states of light. The experimental results have been published in a prestigious Nature Communications journal.

Every information processing task requires a memory. As any classical computer cannot exist without a RAM memory, quantum computer could not be built without a quantum memory. Quantum memory is a device capable of storage and on demand retrieval of quantum states.


This is a cooled and trapped cloud of cold atoms used to realize the quantum memory protocol. The atoms reside in the center of the vacuum chamber, around which the magnetic coils necessary to trap the atoms are visible. The blue color is caused by two near-infrared lasers illuminating the atoms and driving a two-photon transition, which results in spontaneous emission of visible blue light.

Source: FUW, Mateusz Mazelanik

The key parameter of such memory is its capacity, in other words the number of qubits (quantum bits) which the memory can effectively process. Simultaneous operation on many qubits is a key to efficient quantum parallel computation, providing new possibilities in the fields on imaging or communication.

Regardless of significant efforts, the on demand generation of many photons remains a key challenge for many experimental groups dealing with quantum information. For a recently widely-used method of multiplexing many single-photon emitters into one network the complexity of experimental systems grows unfavorably with its advantages.

Using a quantum memory on the other hand one can generate a group of a dozen photons within seconds rather than years. Among many methods of encoding information about single photons in a quantum memory the spatial multiplexing aided by a single-photon sensitive camera stands out as an effective way to obtain high capacity at low cost.

In the Quantum Memories Laboratory (Faculty of Physics, University of Warsaw) such high-capacity memory has been successfully built. The system now holds a world-record of the largest capacity, as other experimentalists can only harness tens of independent states of light. The heart of the constructed setup comprises a so-called magneto-optical trap (MOT): a group of rubidium atoms inside a glass vacuum chamber is trapped and cooled by lasers in the presence of magnetic field to about 20 microkelvins. The memory light-atoms interface is based on off-resonant light scattering.

In the write-in process the cloud of atoms is illuminated by a laser beam, resulting in photon scattering. Each scattered photon is emitted in random direction and registered on a sensitive camera. The information about scattered photons is stored inside the atomic ensemble in the form of collective excitations - spin-waves which can be on demand retrieved as another group of photons.

By measuring correlations between emission angles of photons created during the write-in and read-out process we certify that the memory is indeed quantum and that the properties of generated state of light fail to be described by classical optics. The prototype quantum memory from Faculty of Physics at University of Warsaw now takes two optical tables and functions with the help of nine lasers and three control computers.

The quantum memory created using the funding of National Science Center (Poland) "PRELUDIUM" and "OPUS" project as well as Ministry of Science and Higher Education "Diamentowy Grant" project stands out for one more reason. The quantum information about all stored photons resides in a single cloud of cold atoms, and each atom takes part in the storage of each photon, making the memory resilient to a decoherence. This has been confirmed by observing quantum interference of two distinct excitations (differing by just a single quantum number).

"This will allow even more complex manipulations of the atomic state, finally to prepare quantum states of light with accurately controlled parameters" - explains prof. Wojciech Wasilewski, head of Quantum Memories Laboratory.

###

Movie: A day from Quantum Memories Laboratory

Physics and Astronomy first appeared at the University of Warsaw in 1816, under the then Faculty of Philosophy. In 1825 the Astronomical Observatory was established. Currently, the Faculty of Physics' Institutes include Experimental Physics, Theoretical Physics, Geophysics, Department of Mathematical Methods and an Astronomical Observatory. Research covers almost all areas of modern physics, on scales from the quantum to the cosmological. The Faculty's research and teaching staff includes ca. 200 university teachers, of which 88 are employees with the title of professor. The Faculty of Physics, University of Warsaw, is attended by ca. 1000 students and more than 170 doctoral students.

SCIENTIFIC PAPERS:

"Wavevector multiplexed atomic quantum memory via spatially-resolved single-photon detection"

M. Parniak, M. Dabrowski, M. Mazelanik, A. Leszczynski, M. Lipka, W. Wasilewski

Nature Communications 8, 2140 (2017); DOI: 10.1038/s41467-017-02366-7

https://www.nature.com/articles/s41467-017-02366-7

CONTACTS:

Dr. Wojciech Wasilewski
Institute of Experimental Physics, Faculty of Physics, University of Warsaw
tel. +48 22 5532630
email: wojciech.wasilewski@fuw.edu.pl

M. Sc. Michal Parniak
Institute of Experimental Physics, Faculty of Physics, University of Warsaw
tel. +48 22 5532629
email: michal.parniak@fuw.edu.pl

M. Sc. Michal Dabrowski
Institute of Experimental Physics, Faculty of Physics, University of Warsaw
tel. +48 22 5532629
email: mdabrowski@fuw.edu.pl

RELATED LINKS:

http://www.fuw.edu.pl
Faculty of Physics, University of Warsaw.

http://psi.fuw.edu.pl/
Quantum Memories Laboratory, Institute of Experimental Physics, Faculty of Physics, University of Warsaw.

http://www.fuw.edu.pl/informacje-prasowe.html
Press Office of the Faculty of Physics, University of Warsaw.

IMAGES:

FUW171215b_fot01s.jpg
HR: http://www.fuw.edu.pl/press/images/2017/FUW171215b_fot01.jpg
Cooled and trapped cloud of cold atoms used to realize the quantum memory protocol. The atoms reside in the center of the vacuum chamber, around which the magnetic coils necessary to trap the atoms are visible. The blue color is caused by two near-infrared lasers illuminating the atoms and driving a two-photon transition, which results in spontaneous emission of visible blue light.
(Source: FUW, Mateusz Mazelanik)

FUW171215b_fot02s.jpg
HR: http://www.fuw.edu.pl/press/images/2017/FUW171215b_fot02.jpg
Article authors: (first row, from left): M. Parniak, M. Mazelanik, M. Dabrowski, M. Lipka, (second row, from left) A. Leszczynski, W. Wasilewski, along with the setup of cold-atom quantum memory.
Two optical tables with elements used to construct the prototype setup are visible. (Source: FUW, Mateusz Mazelanik)

MOVIES:

https://www.youtube.com/watch?v=WYhX4Gt3VCw A day from Quantum Memories Laboratory (Source: FUW, Michal Parniak)

Michal Dabrowski | EurekAlert!

More articles from Physics and Astronomy:

nachricht Flying Laptop satellite mission extended by two years - Successfully in orbit since July 14, 2017
16.07.2019 | Universität Stuttgart

nachricht Robert Alfano team identifies new 'Majorana Photons'
16.07.2019 | City College of New York

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...

Im Focus: Extremely hard yet metallically conductive: Bayreuth researchers develop novel material with high-tech prospects

An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".

The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...

Im Focus: Modelling leads to the optimum size for platinum fuel cell catalysts: Activity of fuel cell catalysts doubled

An interdisciplinary research team at the Technical University of Munich (TUM) has built platinum nanoparticles for catalysis in fuel cells: The new size-optimized catalysts are twice as good as the best process commercially available today.

Fuel cells may well replace batteries as the power source for electric cars. They consume hydrogen, a gas which could be produced for example using surplus...

Im Focus: The secret of mushroom colors

Mushrooms: Darker fruiting bodies in cold climates

The fly agaric with its red hat is perhaps the most evocative of the diverse and variously colored mushroom species. Hitherto, the purpose of these colors was...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

Flying Laptop satellite mission extended by two years - Successfully in orbit since July 14, 2017

16.07.2019 | Physics and Astronomy

New safer, inexpensive way to propel small satellites

16.07.2019 | Power and Electrical Engineering

UCI electrical engineering team develops 'beyond 5G' wireless transceiver

16.07.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>