Experiment

We generate nonclassical (quantum) light from quantum dots, nonlinear crystals, photonic-crystal fibres.

We test this light for photon-number correlations and squeezing.

We use this light for quantum information and photonic technologies.

Location: 
Erlangen
Germany
49° 35' 22.8264" N, 11° 0' 43.0596" E
DE

The Quantum Optics and Information Laboratory (QOIL), founded in 2006, is the home of Geoff Pryde’s research group.

We perform experiments with photons – single particles of light – to investigate quantum information science and to study the fundamental laws of quantum physics. Our work is directed at developing the next generation of information and measurement technologies, whilst revealing the nature of the quantum world.

QOIL is a part of the Centre for Quantum Dynamics at Griffith University. We’re also a key member of CQC2T – the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology – a large Australian-based and internationally-connected focused research initiative. We also conduct other, separately funded, quantum and optics research. The group collaborates with theorists and experimentalists worldwide – a non-exhaustive list includes Oxford University, the National Institute of Standards and Technology (NIST, USA), the National University of Singapore, the University of Bristol, the University of Geneva, the Institute for Quantum Computing at the University of Waterloo (Canada), as well as many other partners.

Our staff and students are tightly integrated into the Australian and international community. They enjoy active collaborations and networking through travel programs, conferences, and lab exchanges, ensuring that they remain at the cutting edge of international research.

QOIL’s facilities are world class: we have developed state-of-the-art sources of single photons and entangled photons, with ultra-high heralding efficiency and photon purity. Our dedicated vibration-damped dark spaces are equipped with high-end lasers, optics, and experimental control hardware. Via our collaboration with NIST, we enjoy the use of high-efficiency fast superconducting nanowire single photon detectors.

Professor Geoff Pryde, the group leader, is excited by the strange quantum world, and by the opportunities to harness it for new technologies. He has led the team to make major advances in quantum computing, long-range entanglement sharing for quantum communication, quantum metrology (precision measurement), and fundamental studies of entanglement and quantum measurements. Geoff is the Deputy Director of the Centre for Quantum Dynamics and a research Program Manager in CQC2T. He is a recipient of the Pawsey Medal of the Australian Academy of Science, and has held an Australian Research Council Future Fellowship.

Location: 
Griffith University
170 Kessels Road Nathan, Queensland
Brisbane
Australia
27° 33' 8.4888" S, 153° 3' 8.0856" E
AU

The group studies atomic and molecular quantum systems with respect to their interactions on different levels of complexity. Of special importance is the application and extension of modern methods for the manipulation and quantum control to many-body quantum systems, in particular using coherent light. The systems under investigation range from highly excited Rydberg atoms over atomic and molecular quantum gases to molecular aggregates. The group develops technologies for trapping and cooling of neutral atoms as well as quantum-state sensitive diagnostics.

Location: 
Physics Institute
Im Neuenheimer Feld 226
Heidelberg
Germany
49° 24' 58.5504" N, 8° 40' 22.8216" E
DE

The section on Quantum Physics and Information Technology at the Physics department of DTU (Technical University of Denmark) is headed by Prof. Ulrik Lund Andersen and conducts experimental research into - among other things - optical quantum information technology, quantum sensing with diamond and mechanical oscillators, and nano-optics.

Research type: 
Location: 
DTU Physics
Fysikvej 309
Kgs. Lyngby
Denmark
55° 47' 8.8008" N, 12° 31' 3.2376" E
DK

Introduction

Atoms are the building blocks of all matter. They have a positively charged nucleus and electron clouds define their outer boundaries. In nature, they remain electrically neutral. The number of electrons governs their chemical properties. All these have long been studied and exploited by mankind. Yet we are just now learning a whole new way of communicating with atoms, and 2 Nobel prizes were given as a result in 1997 and 2002. The atom chip is a chapter in this new dictionary - translating from human language to atom language. This journey may lead to new insights into the foundations of quantum theory, and numerous technological applications.

Many of today's electronic devices are unthinkable without miniaturization. By similarly shrinking elements used in atom optics, such as atom traps, guides, mirrors, beam splitters and interferometers, and by fabricating them using modern solid-state fabrication (lithography) techniques stemming from the well established and rich know-how in electronics and optics, we hope to achieve similar control over atoms as we have over electrons and photons. The preparation, manipulation and measurement sensitivity must reach the level in which delicate quantum effects are dominant.

The basic idea of the atom chip is to have a solid state device produce light, magnetic and electric fields, which would trap, manipulate and measure atoms hovering a few microns outside the device in ultra high vacuum. Hence, we are using much the same technology as the semi conductor chips of today; however, our system is not the electrons running inside the solid device (and hence are subject to lack of isolation), but rather atoms hovering outside it.

What is unique about this new tool box? First, let us note that studying quantum behavior requires isolation of the observed system from its environment because any interaction would quickly destroy the delicate quantum effects. The neutral atom is an excellent choice in this matter: because it has no charge, it interacts with its environment in a relatively weak way.

Second, atom-chips offer an experimental tool box that is robust, scalable (e.g. with arrays of traps) and accurate. Lithographic techniques can now create structures with length scales below 100 nm, which is smaller than the quantum-mechanical (de-Broglie) wavelength of the cooled atoms, ensuring control at the quantum level. The small size of the traps allows atoms to be positioned in individual sites separated by small distances, thus enabling them to interact in a controlled way. The fact that the atoms are well localized (state size of 10nm) also enables to address them for manipulation and detection by extremely local miniaturized light elements such as micro cavities and solid state wave guides, which today may be fabricated in the same fabrication process, thus creating a monolithic device. To enable a complicated web of independent wires and light guides, several layers of structures will be needed on the chip and consequently 3d fabrication will have to be initiated. Finally, a long term goal would be to fabricate on the same chip even the light sources (micro-lasers) and readout electronics, hence realizing a truly integrated self-sufficient device. The hope is that such devices will do for quantum atom optics what integrated circuits did for electronics.

As we are now able to trap and cool the atoms on the atom chip (all the way to nano Kelvin temperatures in a Bose-Einstein Condensate), we are able to control their position and velocity. Furthermore, we also know how to control their internal properties, namely, the state of the electron clouds in the atom, known as hyperfine states. Hence, all relevant parameters can now be controlled and measured. This should bring atom manipulation (matter wave quantum optics) capabilities to a level enabling interesting experiments concerning chaos (using complex field potentials), non-linearity (due to atom-atom interactions), entanglement (atom-atom correlations), atom-light interactions, low dimensional physics and more.

Another issue regarding which the atom-chip may award us with more insight is quantum decoherence. Decoherence is the process responsible for the classical features of our everyday world, despite its underlying quantum nature — it is what happens when a quantum state is destroyed. This elusive border between classical and quantum states has been a source of debate and confusion since the early days of quantum theory. In atom chip experiments, decoherence can be examined in complicated potentials (e.g. double well) and with carefully tailored environments. Furthermore, the very interesting question of surface-induced decoherence can be addressed in detail; indeed it must, as such decoherence may undermine the whole concept of the atom-chip.

What else? Aside from providing researchers with a strong experimental tool with which to probe nature, one might expect in the future to see technological implementations such as miniaturized versions of highly accurate atomic clocks and acceleration sensors, which are already used for precision measurements. Such tiny systems could prove useful for example in navigation systems. Next, the atom-chip could be integrated into quantum communication and encryption systems, which ensure information security, and which are currently being tested in labs. In quantum information, a ‘qubit’ is the quantum equivalent of a classical ‘bit’ of information. So, for example, the atom-chip may enable the conversion of ‘flying qubits’ (photons that can travel distances in optical fibers) into ‘storage qubits’ — atoms that may be kept in a single location for a long time without changing their quantum state. A final example, and the most far reaching, is the quantum computer, for which quantum theory predicts a new type of computing logic, able in some cases, to outrun the present classical computers by many orders of magnitude in processing time. Once further advance is made on issues such as single atom trapping and controlled atom-atom interaction (entanglement) – the basic computational element, the atom chip could turn out to be the obvious choice for building a quantum computer.

Location: 
Ben Gurion University of the Negev Beer Sheva
Israel
31° 15' 10.7028" N, 34° 47' 29.2632" E
IL

We work on applications of quantum optical techniques to spectroscopy and imaging.

Location: 
Faculty of Physics, University of Warsaw
Pasteura 5
Warsaw
Poland
52° 13' 46.8336" N, 21° 0' 44.0244" E
PL

We are an experimental research group located at the University of Cambridge, Cavendish Laboratory. Our primary focus area is Spin-Based Quantum Information Science and Nanoscale Quantum Metrology. For this purpose we are interested in the study and control of spins confined in mesoscopic quantum systems, as well as the interface of spin and photon states. The physical systems we are investigating range from self-assembled quantum dots and diamond-based emitters for coherent control of spin states to metal-dielectric hybrid nanostructures for efficient and tailored light-matter interaction.

Research type: 
Location: 
Cavendish Laboratory - University of Cambridge
JJ Thomson avenue
Cambridge
United Kingdom
52° 12' 37.5264" N, 0° 5' 26.8548" E
GB

Developers of ARTIQ, a next-generation control system for quantum information experiments.

Research type: 
Location: 
Hong Kong
Hong Kong S.A.R., China
HK
Research type: 
Location: 
University of Rome La Sapienza
Piazzale Aldo Moro 5
Roma
Italy
41° 54' 12.0924" N, 12° 30' 55.5336" E
IT