At a Glance

Founded2002
Renewal dates2007, 2012
Members34
Disciplines
Computer science, including quantum computing and theory of computation; quantum, condensed matter, mathematical and atomic physics; optics; electronic and information engineering; applied mathematics

How do we build a quantum computer?

Today’s digital world is binary: a switch is either on or off, one or zero. But in the subatomic world of quantum physics, different rules hold sway. Some particles can exist in two or more states simultaneously. Others can react instantly to changes taking place miles away. These properties could allow us to build computers entirely unlike those we have today. Quantum computation could allow us to break unbreakable codes, model impossibly complex phenomena and solve problems previously thought to be unsolvable.

Our unique approach

Quantum information science exists at the interface between computer science and quantum physics. For this reason, it is inherently interdisciplinary, requiring input from experts in many different fields. CIFAR brings together 35 leading researchers from mathematics, computer science, cryptography, theoretical physics, experimental physics, chemistry, engineering and other relevant disciplines. Together, these researchers aim to harness the power of quantum mechanics and create exponentially more powerful computers.

Wallraff - Section of superconducting chip - 2015
Superconducting chips like this one provide one way create the qubits necessary for quantum computing. (Image courtesy of Marek Pechal, Quantum Device Lab, ETH Zurich)

Why this matters

Quantum computing could affect society on a scale similar to that of the digital computer revolution. When researchers solve the theoretical and practical problems, quantum computing promises to vastly increase the computational speed, security and power available to us.

 In 1994, mathematician Peter Shor published a famous algorithm about calculating the prime factors of very large numbers. This is a task that would take classical computers millions of years, but Shor’s algorithm showed that a quantum computer could do it in minutes. Not only did this provide a concrete example of a problem that only quantum computers could solve, it also had serious implications for the world of computer security. Many common cryptography algorithms — the technology used to keep banking transactions and other sensitive information secret — rely on the fact that factoring large numbers is something that cannot quickly be done by classical computers. If a quantum computer could be built, it could break almost any existing security code and allow for more secure cryptography.

 In addition to cryptography, quantum computation could solve difficult optimization problems — that is, selecting the best solution out of a large set of possible answers. Examples include finding a drug molecule that would bind to a particular target in the human body, or choosing the best price at which to sell a product in a crowded and complex market. If quantum computers can solve those problems more quickly than classical computers, they could have huge implications for banking, medicine, defence and many other fields.

Data-compression-image
Aephraim M. Steinberg showed that quantum information stored in a collection of identically prepared qubits can be perfectly compressed into exponentially fewer qubits

In depth

Researchers in the program are exploring fundamental questions about what exactly a quantum computer will be capable of, and how one can be built. In many cases they have done important groundwork in the field. Program Director Raymond Laflamme, for instance, laid down the fundamental mathematical work behind the quantum error-correcting codes that will be necessary for a working quantum computer. Advisor David Cory was the first to experimentally demonstrate that nuclear magnetic resonance technology could be used for quantum computation. Senior Fellow Gilles Brassard is the co-inventor of the first quantum cryptography algorithm.

The program’s experimentalists work closely with theorists to create systems in which quantum behaviour can be controlled and exploited. In these systems, qubits consisting of photons or other quantum particles are being manipulated using the quantum phenomena of superposition and entanglement in order to store, retrieve and transmit information.

CIFAR’s quantum information science program is organized around three major themes:

  • Where does the power of quantum computation come from?

Even if the final form of quantum computers remains undecided, mathematicians and theoretical physicists can still design quantum algorithms and compare their performance with conventional computer programs. These researchers aim to find problems for which quantum computation offers a real advantage.

For example, a team of CIFAR researchers led by Fellow David Poulin recently showed that quantum computations could be used to simulate the behaviour of atoms in molecules more accurately than conventional computer models. Advanced quantum models could be used to design new drugs or high-performance materials.

  • How can we control quantum systems?

In order to get qubits to show quantum behaviour, they need to be isolated from heat or any other external source of energy. This is one of the major challenges to building a working quantum computer. Generally, quantum computing devices are built using materials that have been super-cooled to temperatures near absolute zero. Other tools of the trade include superconductors, lasers and advanced sensors tuned to measure quantum properties. For example, a team led by Associate Fellow Amir Yacoby recently proposed a way to use tiny magnetic particles to amplify the nuclear spin of qubits so they can be more easily measured.

The goal is to be able to reliably write information to qubits by changing their properties, and later to read this information back. Laflamme has built a working model containing a dozen qubits. An international team led by Fellow Thomas Jennewein has created a system capable of transmitting quantum information over hundreds of kilometers.

Such systems, if interlinked through a network of satellite and ground stations, could serve as the basis of a ‘quantum internet’. Jennewein’s team has also demonstrated a system that links three widely separated qubits through quantum entanglement

  • What would quantum cryptography look like?

Quantum computers could easily break most modern forms of computer cryptography. But they could also create new forms of cryptography thanks to the principle of entanglement. If a sender and receiver each have one of an entangled pair of qubits, they could send information between them in a highly secure way. Even if an interloper did try to take a peek at the information, the mere act of observation would affect the pairs and send an alert that the message had been compromised. This system, known as quantum key distribution, is being tested experimentally by CIFAR researchers like Jennewein. His Quantum EncrYption and Science Satellite (QEYSS) project aims to demonstrate the generation of encryption keys through the creation of quantum links between ground and space.

Selected Papers

Knill, E., Laflamme, R., Milburn, G.J. (2001) A scheme for efficient quantum computation with linear optics. Nature 409: 46-52

Negrevergne, C., Mahesh, T.S., Ryan, C.A., Ditty, M., Cyr-Racine, F., Power, W.,  Boulant, N., Havel, T., Cory, D.G., Laflamme, R. (2006) Benchmarking quantum control methods on a 12-qubit system. Physical Review Letters, 96: 170501 and also Virtual Journal of Nanoscale Science & Technology – May 15, 2006 Volume 13, Issue 19. arXiv:quant-ph/0412076

L. A. Rozema et al., “Quantum Data Compression of a Qubit Ensemble,” Physical Review Letters 113, 16 (2014) doi: http://dx.doi.org/10.1103/PhysRevLett.113.160504.

J. Zhang et al., “Digital quantum simulation of the statistical mechanics of a frustrated magnet,” Nature Communications 3, 880 (2012) doi:10.1038/ncomms1860.

 

READ 2016’s ANNUAL UPDATE 

 

Fellows & Advisors

Photo of Raymond Laflamme

Raymond Laflamme

Program Director

Raymond Laflamme’s research interests are theoretical methods for error control in quantum devices, the use of quantum computers to simulate quantum systems and experimental implementation of small quantum information processing devices…

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Fellows

Scott Aaronson

Associate Fellow

Massachusetts Institute of Technology

United States

Alexandre Blais

Fellow

Université de Sherbrooke

Canada

Gilles Brassard FRS

Senior Fellow

Université de Montréal

Canada

Raffi Budakian

Senior Fellow

University of Waterloo

Canada

Paola Cappellaro

Associate Fellow

Massachusetts Institute of Technology

United States

Andrew Childs

Senior Fellow

University of Maryland

United States

Richard E. Cleve

Senior Fellow

University of Waterloo

Canada

William A. Coish

Fellow

McGill University

Canada

Joseph Emerson

Fellow

University of Waterloo

Canada

Daniel Gottesman

Senior Fellow

Perimeter Institute for Theoretical Physics

Canada

Patrick Hayden

Senior Fellow

Stanford University

United States

Peter Høyer

Associate Fellow

University of Calgary

Canada

Thomas Jennewein

Fellow

University of Waterloo

Canada

Debbie Leung

Fellow

University of Waterloo

Canada

Hoi-Kwong Lo

Associate Fellow

University of Toronto

Canada

Alexander Lvovsky

Fellow

University of Calgary

Canada

Michele Mosca

Senior Fellow

University of Waterloo, Perimeter Institute for Theoretical Physics

Canada

Ashwin Nayak

Associate Fellow

University of Waterloo

Canada

Michel Pioro-Ladrière

Fellow

Université de Sherbrooke

Canada

David Poulin

Fellow

Université de Sherbrooke

Canada

Robert Raußendorf

Fellow

University of British Columbia

Canada

Barry C. Sanders

Senior Fellow

University of Calgary

Canada

Aephraim M. Steinberg

Senior Fellow

University of Toronto

Canada

Barbara Terhal

Associate Fellow

RWTH Aachen University

Germany

Wolfgang Tittel

Senior Fellow

University of Calgary

Canada

Andreas Wallraff

Associate Fellow

ETH Zurich

Switzerland

John Watrous

Senior Fellow

University of Waterloo

Canada

Gregor Weihs

Fellow

University of Innsbruck

Austria

Amir Yacoby

Associate Fellow

Harvard University

United States

Bei Zeng

Fellow

University of Guelph

Canada

Advisors

Charles H. Bennett

Advisor

IBM Corporation

United States

Harry M. Buhrman

Advisor

Centrum voor Wiskunde en Informatica (CWI)

The Netherlands

David G. Cory

Advisory Committee Chair

University of Waterloo Perimeter Institute for Theoretical Physics

Canada

Andrew Yao

Advisor

Tsinghua University

China

Global Scholars

Nir Bar-Gill

CIFAR Azrieli Global Scholar

The Hebrew University of Jerusalem

Israel

Giulio Chiribella

CIFAR Azrieli Global Scholar

University of Hong Kong

China

Gerhard Kirchmair

CIFAR Azrieli Global Scholar

University of Innsbruck

Austria

Program Timeline

Program launches

CIFAR launches the program in Quantum Information Processing amidst widespread

Quantum walk speeds up algorithm

CIFAR Senior Fellow Richard Cleve (University of Waterloo) and collaborators

Geometry proves useful for studying quantum entanglement

CIFAR Fellow Patrick Hayden (McGill University) and colleagues participate in

Nuclear magnetic resonance quantum computing advances

CIFAR Program Director Raymond Laflamme’s University of Waterloo laboratory makes

Proving what quantum computers can’t do

CIFAR Fellow Andris Ambainis (University of Latvia) introduces a new

Quantum algorithm speeds up search

CIFAR Fellow Ashwin Nayak (University of Waterloo) and collaborators design

Quantum security faults found

CIFAR Fellow Hoi-Kwong Lo (University of Toronto) and collaborators demonstrate

Quantum computing helps classical computing

CIFAR Fellow John Watrous (University of Waterloo) and collaborators show

Quantum devices can handle faults

CIFAR Senior Fellow Michele Mosca (University of Waterloo) and others

New cryptographic protocols for secure communication

Fellow Gilles Brassard (University of Montreal) and Scholar Peter Høyer

A quantum satellite proposed

CIFAR Fellow Thomas Jennewein (University of Waterloo) proposes a quantum

Quantum dots controlled

CIFAR Fellow Gregor Weihs (Universität Innsbruck) and collaborators succeed in

New system performs quantum computing on encrypted data

CIFAR Fellow Thomas Jennewein (University of Waterloo), CIFAR Global Scholar

A new way to test quantum devices

CIFAR Fellow Alexander Lvovsky, Senior Fellow Barry Sanders (both University

The first Quantum Information Processing meeting was held shortly in May 2003, shortly after the program’s launch

2002

Program launches

CIFAR launches the program in Quantum Information Processing amidst widespread excitement about the possibilities in this young, promising area of research. Many questions remain unanswered about the nature of quantum information, and experimentalists are in hot pursuit of technologies that can encode information in quantum bits. The experts say they need the best minds and support from CIFAR to pursue risky, long-term research directions — with theorists and experimentalists collaborating together — to make progress in a field that could change our world.

2003

Quantum walk speeds up algorithm

CIFAR Senior Fellow Richard Cleve (University of Waterloo) and collaborators produce an example of a quantum walk — a quantum analog of a classical algorithm tool called a random walk — that greatly reduces the amount of time needed to solve a certain type of problem. This proves in principle that classical methods take exponentially more time than quantum approaches to solve certain types of problems.

2003

Quantum entanglement improves remote communication

CIFAR Senior Fellow Gilles Brassard, Fellow Alain Tapp (both University of Montreal) and others establish a fundamental relationship between the enigmatic structure of quantum theory and the concrete achievability of communication tasks. They show that even though quantum entanglement cannot be used to transmit information between remote parties, it can reduce the amount of communication needed for computing tasks. They prove it is possible for two separated parties to compute arbitrary functions of their inputs, with only a trivial amount of communication.

2004

Geometry proves useful for studying quantum entanglement

CIFAR Fellow Patrick Hayden (McGill University) and colleagues participate in a “grand unification” of concepts in quantum information theory. Hayden finds that something called the random subspace method, which originates geometry, is useful for studying quantum entanglement. He and collaborators identify a master protocol from which many others can be immediately inferred. The research could help with communication.

A diagram showing the architecture for quantum computing using quantum electrodynamics

2004

A new way to study light and matter

CIFAR Fellow Alexandre Blais (Université de Sherbrooke) and others propose an architecture for quantum computing using quantum electrodynamics for superconducting electrical circuits. The system provides a fundamental way to study the interaction of light and matter. With these superconductors, circuits can be fabricated to behave like atoms (superconducting qubits) or as a cavity does for an atom.

Raymond Laflamme in his lab

2005

Nuclear magnetic resonance quantum computing advances

CIFAR Program Director Raymond Laflamme’s University of Waterloo laboratory makes significant progress in the area of nuclear magnetic resonance (NMR) quantum computing, which uses the spin states of molecules as qubits, or quantum bits. For example, they demonstrate new algorithmic techniques to cool systems to the low temperatures needed for success. In addition, they demonstrate many forms of quantum control and quantum error correction in medium-sized molecules.

A diagram showing the new method of proving boundaries in a quantum computation model that has been widely applicable to quantum algorithms

2006

Proving what quantum computers can’t do

CIFAR Fellow Andris Ambainis (University of Latvia) introduces a new methodology for proving the limits of what quantum computers can do, meaning which problems are too complex even for a quantum computer to solve. This becomes an important and widely applicable tool, as most known quantum algorithms can be cast in this model and these limits, or lower bounds, can be used to provide evidence that algorithms are optimal.

2006

The trouble with spin chains determined

CIFAR Senior Fellow Daniel Gottesman (Perimeter Institute for Theoretical Physics), with collaborators from Caltech Institute for Quantum Information, identifies that a one-dimensional spin chain with short-range interactions can be as hard to simulate as the most general quantum problem in any dimension. This breakthrough has implications for many-body quantum physics, being that one-dimensional quantum spin-glasses are possible.

An illustration of the classic zero-knowledge proof concept, showing how Peggy can prove she knows a secret password without telling Victor. She chooses either path A or B randomly, then Victor shouts an exit path. If she knows the password to cross the middle gate, she will always exit at the gate he names

2006

Secret verification proved possible for quantum information

CIFAR Fellow John Watrous (University of Waterloo) single-handedly resolves an outstanding question in theoretical computer science related to security. He studies “zero-knowledge” proof systems, which are protocols in which one party — the prover — tries to convince another — the verifier — that a fact is true without telling them the fact itself. A common example involves a girl named Peggy trying to prove to her friend Victor that she knows the secret word to open a door, without telling Victor the word. Researchers thought this concept couldn’t be applied to quantum information as it is in classical information, but Watrous shows that the concept carries over into the quantum realm. He develops a technique that allows several protocols to remain zero-knowledge against quantum attacks.

2007

Quantum algorithm speeds up search

CIFAR Fellow Ashwin Nayak (University of Waterloo) and collaborators design a new quantum algorithm that converts any random walk into a quantum one and uses it to speed up search algorithms. Advantages of this algorithm include conceptual and technical simplicity, improved efficiency and demystification of the role of quantum walks in search algorithms.

CIFAR Fellow Andris Ambainis discovered an algorithm that determines whether or not a sequence contains repeated elements

2007

Quantum walk algorithm plays match

CIFAR Fellow Andris Ambainis (University of Waterloo) discovers a quantum walk-based algorithm for a problem called “element distinctness.” Given a list of numbers, the algorithm must determine whether or not it contains two that are equal. This algorithm is applicable to the design of further quantum algorithms for some graph problems and matrix identity problems.

Credit: Credit: Hoi-Kwong Lo

The research of CIFAR Associate Fellow Hoi-Kwong Lo and his lab highlighted the need for stronger testing of quantum security systems. Here, the experimental setup includes two receivers named Bob and Alice, according to convention

2008

Quantum security faults found

CIFAR Fellow Hoi-Kwong Lo (University of Toronto) and collaborators demonstrate how the imperfect implementation of some commercial implementations of quantum key distribution (QKD) systems could be hacked. This breakthrough supports subsequent development of a method to certify QKD systems.

Credit: Credit: Google Maps and Gregor Weihs

The first Canadian free space quantum key distribution system is in Waterloo, with a total separation of 1575 m between the entangled photon pairs

2008

Quantum cryptography deployed in Waterloo

CIFAR Fellow Gregor Weihs (Universität Innsbruck), Program Director Raymond Laflamme (University of Waterloo) and collaborators deploy a free space cryptography system using a source of entangled photons that is free from hacking flaws. This system is deployed in Waterloo, making it the first Canadian free space QKD system and a founding block for the development of quantum technologies in Canada.

CIFAR Senior Fellow John Watrous shows that quantum computation can yield new results in classical computer science

2009

Quantum computing helps classical computing

CIFAR Fellow John Watrous (University of Waterloo) and collaborators show that quantum computation can yield new results in classical computer science, marking a major breakthrough in the field. They use ideas from learning theory to produce a parallel algorithm for a type of optimization problem known as semidefinite programs. Their results deepen the connection between quantum algorithms and semidefinite programs.

CIFAR Fellows Jay Gambetta and Alexandre Blais demonstrate the first solid state device capable of quantum information processing

2009

Superconducting quantum processor built

CIFAR Global Scholar Jay Gambetta (University of Waterloo), Fellow Alexandre Blais (Université de Sherbrooke) and a team of physicists from Yale University create a two-qubit superconducting quantum processor — a step toward building a quantum computer. They also use the two-qubit superconducting chip to successfully run elementary algorithms, such as a simple search, demonstrating quantum information processing with a solid-state device for the first time. Their groundbreaking research is described in Nature.

2009

Quantum algorithm simulations

CIFAR fellows make it easier to invent and discover new algorithms by unifying different kinds of quantum algorithms. Richard Cleve, Michele Mosca (both University of Waterloo), Daniel Gottesman (Perimeter Institute for Theoretical Physics), Barry Sanders (University of Calgary) and collaborators show that certain quantum algorithms can be used to simulate others, effectively translating non-standard algorithms into “standard” ones with little or no slowdown.

2010

Quantum devices can handle faults

CIFAR Senior Fellow Michele Mosca (University of Waterloo) and others shows that even imperfect quantum devices can be good enough to continue operating if some of their components fail — an important step towards practical implementations of quantum computing.

Credit: Credit: Raymond Laflamme

Single photon source impinging on a 3 slit aperture. The apertures can be individually opened or closed to test the validity of Born's rule for multi-order interference. The resultant interference pattern demonstrates the wave-particle duality in quantum mechanics

2010

Quantum law confirmed

CIFAR fellows Raymond Laflamme, Thomas Jennewein (both University of Waterloo) and Gregor Weihs (Universität Innsbruck) use optics to perform experiments that test contextuality in quantum ensembles, a considerable advancement in the field. Their discovery rules out the existence of higher-order interferences experimentally and thereby confirms an axiom in quantum physics known as Born's rule, which determines the probability of a measurement on a quantum system yielding a certain result.

2010

Quantum privacy protocol developed

CIFAR Senior Fellow Gilles Brassard (Université de Montréal), motivated by interactions with other fellows including Global Scholar Anne Broadbent (University of Ottawa) and fellows Claude Crépeau (McGill University) and Alain Tapp (Université de Montréal), develops quantum protocols for oblivious transfer and “blind” quantum computation, where a user can arrange for a quantum server to carry out a computation while maintaining the user’s privacy about the nature of the computation. This advances our understanding of security and privacy in a quantum world.

2011

New cryptographic protocols for secure communication

Fellow Gilles Brassard (University of Montreal) and Scholar Peter Høyer (University of Calgary) and their collaborators demonstrate a significant milestone in post-quantum cryptography — the study of cryptosystems. They discover new cryptographic protocols that make possible the secure exchange of private information between two conventional computers, even if a would-be eavesdropper has the powerful advantage of quantum computing.

Credit: Credit: Michel Pioro-Ladriere

CIFAR Fellows Sachrajda and Pioro-Ladriere were able to manipulate the spins of quantum dots with the nano-scale device shown

2011

Three spin states manipulated

CIFAR Fellow Andrew Sachrajda (National Research Council) and Scholar Michel Pioro-Ladrière (Université de Sherbrooke) are part of a team that achieve a breakthrough in quantum computing. For the first time, they manipulate the spin states of three interacting electrons. The result is a significant leap forward in the effort to develop semiconductor quantum circuits, in which electron spins serve as quantum bits, or qubits. Spin is an intrinsic magnetic property of electrons, and its direction can be either ‘up’ or ‘down.’ Learning to control and manipulate spin holds the potential to advance both fundamental science and new applications.

Credit: Credit: Aephraim Steinberg

3D plot showing how a photon can behave like a wave and a particle

2011

Uncertainty principle skirted

Performing a “new take” on an iconic physics experiment, Fellow Aephraim Steinberg (University of Toronto), Global Scholar Krister Shalm (University of Waterloo) and other collaborators skirt a challenging fundamental rule of quantum mechanics: that any attempt to directly observe or measure a quantum system actually alters it. They demonstrate for the first time a way to successfully trace the pathways travelled by photons – quantum particles of light – through two slits and on to a screen without disrupting their behaviour. Steinberg and his collaborators get around this longstanding problem using “weak measurement,” a technique that obtains only very little information about each particle. Because the measurement is so weak, the particle’s behaviour is not significantly altered. By repeating the weak measurements many times on different particles, the team is able to plot the average path the particles travelled. These results demonstrate that a quantum system can behave like a wave and a particle at the same time.

Credit: Credit: SPIE

Schematic drawing of the proposed Quantum EncrYption and Science Satellite (QEYSSat) spacecraft

2012

A quantum satellite proposed

CIFAR Fellow Thomas Jennewein (University of Waterloo) proposes a quantum satellite, dubbed QEYSSat, to demonstrate the capacity for global quantum communication and enable scientists to test the fundamental properties of quantum mechanics on an unprecedented scale. The proposal follows an experiment by an international research team including Jennewein that achieved a record-breaking quantum teleportation distance of 143 kilometres in 2012, transferring quantum information between two of the Canary Islands. The experiment suggests that a satellite-based quantum communications system is practical. The Canadian Space Agency supports technical studies and explores a prospective mission.

Credit: Credit: Nature

A graphic showing an elementary lattice cell. Qubits (spheres) are encoded on the faces and edges

2012

Topological quantum computation reduces error rate

CIFAR Fellow Robert Raussendorf (University of British Columbia) demonstrates that topological error correction is valid. Topological error correction, which combines topological quantum computation with quantum error correction, is a promising approach for ensuring that a quantum computer can solve complex problems even if there are faults in its operation. Raussendorf and colleagues show how this method can protect computations against an error on a quantum bit and reduce the overall error rate significantly.

CIFAR Program Director Ray Laflamme

2012

A step toward quantum error correction

CIFAR Senior Fellow Raymond Laflamme’s group (University of Waterloo) performs experimental demonstrations of multiple rounds of algorithmic cooling using NMR. The results of these experiments help identify the challenges for performing quantum simulations of physical systems at finite temperatures, and suggest methods that may be useful in simulating thermal open quantum systems. This result, together with their demonstrations, is a step closer towards quantum error correction.

CIFAR Fellow Gregor Weihs

2013

Quantum dots controlled

CIFAR Fellow Gregor Weihs (Universität Innsbruck) and collaborators succeed in controlling quantum dots – semiconductor nanostructures in which motion can only take place in one dimension – more accurately than ever before. They have since used this technique to generate entangled photon pairs, which are an important resource for quantum communication.

Credit: Credit: Arjan van Loo

An illustration of the artificial atoms or “qubits” alongside the one-dimensional “waveguide” or transmission line

2013

Artificial atoms interact at a distance

CIFAR fellows demonstrate for the first time that artificial atoms can work collectively rather than independently of each other to share light. CIFAR Fellow Alexandre Blais (Université de Sherbrooke) and CIFAR Senior Fellow Barry Sanders (University of Calgary), both theoretical physicists, collaborate with CIFAR Associate Andreas Wallraff (ETH Zurich), an experimentalist in superconducting quantum electronics, and other researchers, to design, build and test a system of artificial atoms. They connect artificial atoms along a narrow superconducting electrical wire which serves as a waveguide. The connected atoms work as a single system, linked by the quantum interaction of exchanging photons. The interaction continues even when the artificial atoms are separated by two centimetres – a huge distance in quantum terms — and is expected to persist at even greater distances.

2013

New model accounts for wave-like behaviour

Computer scientist and Fellow Peter Høyer collaborates with physicist and Senior Fellow Barry Sanders (both University of Calgary) and a Ph.D. student to create a new model that takes into account the wave-like behaviour of quantum particles. It uses continuous variables, which can hold any possible value within a range. The model also uses harmonic oscillators – a system taken from physics to characterize wave motion. Testing their model on a well-known quantum algorithm, the team shows that taking advantage of the natural modulation in quantum systems leads to more accurate solutions than attempting to fit quantum behaviour into a discrete model. The result implies that it is better to adapt computational problems to physical properties than the other way around.

2014

New system performs quantum computing on encrypted data

CIFAR Fellow Thomas Jennewein (University of Waterloo), CIFAR Global Scholar Anne Broadbent (University of Ottawa) and CIFAR Global Scholar Alumnus L. Krister Shalm (National Institute of Standards and Technology) develop a system for carrying out quantum computing on encrypted data. The method enables quantum computers to solve complex problems using sensitive data, keeping the data encrypted throughout the process. The experiment uses single particles of light, or photons, to carry information. After sending encrypted quantum bits (qubits) to the server, the researchers demonstrate that a simple interactive process between the client and the server enables perfectly private remote quantum computations. This collaborative work is initiated at a CIFAR meeting, where discussions bridge the gap between theory and practice.

2014

Classical physics found to be contained within quantum physics

CIFAR Fellow Robert Raussendorf (University of British Columbia), CIFAR Fellow Joseph Emerson (University of Waterloo) and collaborators achieve an important breakthrough on the power of quantum computation. They consider a particular model of quantum computation, so-called measurement-based quantum computation, and then they search for its classical counterpart.  They confirm that classical physics is contained in quantum physics as a limit and that this is true for computation in particular.  The result of the research emphasizes a need for better understanding of the key quantum properties that make a quantum computer work.

2014

Quantum information shown to compress

CIFAR Senior Fellow Aephraim Steinberg (University of Toronto), CIFAR Global Scholar alumnus Alex Hayat (Technion – Israel Institute of Technology) and collaborators show that quantum information stored in a collection of identically prepared quantum bits, or qubits, can be perfectly compressed into exponentially fewer qubits without losing information. Steinberg’s team shows that the information contained in three qubits can be compressed into two, and that this compression would scale exponentially, such that only 20 qubits could store all the information about one million qubits. Selected by Physics World as one of the top ten physics breakthroughs of the year, this result suggests potential future efficiencies in quantum communications and information storage.

CIFAR Fellow Lvovsky and a postdoctoral student

2015

A new way to test quantum devices

CIFAR Fellow Alexander Lvovsky, Senior Fellow Barry Sanders (both University of Calgary) and collaborators discover a unique way of testing quantum devices to determine their function and accuracy. They develop a highly accurate method for analyzing quantum optical processes using standard optical techniques involving lasers and lenses — a discovery that may lead the way towards a quantum certification process.

Credit: Credit: Riley Brandt / University of Calgary

University of Calgary postdoctoral fellows and PhD students Erhan Saglamyurek, left, Daniel Oblak, and CIFAR Senior Fellow Wolfgang Tittel

2015

A step toward quantum internet

CIFAR Senior Fellow Wolfgang Tittel (University of Calgary) and collaborators demonstrate that a major obstacle to building a quantum information network can be overcome. They show that particles of light, or photons, can be faithfully stored and retrieved at telecommunication wavelengths in a commercially available erbium-doped fibre. This fibre is already used in today’s communication networks; here, it is re-purposed to store quantum light. To make this discovery, the researchers cool the fibre to nearly absolute zero temperature and assess its viability for quantum storage by using “entangled” pairs of photons.

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