Measurement-based quantum computing and its relation to other quantum models
Lead Research Organisation:
University of Edinburgh
Department Name: Sch of Informatics
Abstract
My research proposal focuses on the field of quantum computation and information theory, a rapidly growing cross-disciplinary field of great importance from both a fundamental and technological perspective. As predicted by Moore's law, the miniaturisation has been the key element in the highly successful quest for more powerful information processing devices in the recent decades. However these advances reach now a fundamental limit where one can no longer ignore microscopic quantum phenomena, and needs quantum engineering to take the challenge.Fortunately, various physical implementations bring quantum computers closer to a reality, while theoretical results exhibit several remarkable advantages of quantum computers over classical ones. It has been predicted that any large-scale overhaul of information science in the 21st century will have to include quantum information. This is evident from the launch of start-up companies which conduct research on quantum information processing such at Quantique, MagiQ and D-Waves, as well as from the creation of quantum research teams within well established firms such as IBM, Microsoft and HP.This research proposal specifically targets a novel form of quantum information processing, called measurement-based quantum computing (MQC), where the key twin notions that distinguish quantum information processing from its classical counterpart, that is Entanglement (creating non-local correlations between quantum elements),and Measurement (observing a quantum system), are the explicit driving force of computation. Such a new paradigm has been so far mainly investigated by physicists with a specific focus on implementation, involving many research groups in UK. I propose to investigate the more computational and mathematical sides, and exploit the main characteristic of this model, namely that any computation can be broken down into a round of global operations (involving more than one quantum element), and a subsequent round of only local ones (together with classical communication). This has potential consequences in the particular questions I wish to address: what is the depth complexity of such computations (how many low-level operations can be applied simultaneously), are there hitherto unknown classes of computations one can realise with strong constraints on the needed quantum resources (using a polynomial number of quantum elements), can we design new commitment protocols (some party is committing to a choice only to be revealed at a later time of his choice), and hiding protocols (some party is drawing on another's computing resources without revealing what for), and perhaps more ambitiously new MQC-specific schemes for redundant computations that will protect computations from errors induced by unavoidable contacts with the environment. A positive answer to one of the above questions would lend further credence in the MQC model as a strong contender in the elusive search for a scalable implementation of quantum computing.
Organisations
People |
ORCID iD |
Elham Kashefi (Principal Investigator) |
Publications
Salek S
(2011)
Programmable Hamiltonian for One-way Patterns
in Electronic Notes in Theoretical Computer Science
Morimae Tomoyuki
(2015)
GROUND STATE BLIND QUANTUM COMPUTATION ON AKLT STATE
in QUANTUM INFORMATION & COMPUTATION
Kashefi E
(2009)
Twisted Graph States for Ancilla-driven Universal Quantum Computation
in Electronic Notes in Theoretical Computer Science
Kashefi E
(2009)
Information Flow in Secret Sharing Protocols
in Electronic Proceedings in Theoretical Computer Science
Fitzsimons J
(2017)
Unconditionally verifiable blind quantum computation
in Physical Review A
Dunjko V
(2012)
Blind quantum computing with weak coherent pulses.
in Physical review letters
Dunjko V
(2010)
Algebraic characterisation of one-way patterns
in Electronic Proceedings in Theoretical Computer Science
DUNJKO V
(2013)
Extended phase map decompositions for unitaries
in Mathematical Structures in Computer Science
Description | We have explored the potential of quantum information theory from its formal and foundational aspects to actual cryptographic experiments through this grant. We have developed the rigorous mathematical model underlying the measurement-based quantum computing and information flow analysis paving the road for wider access to such models among different sub-disciplines within computer science (more than 600 joint citations). Key highlights are described next. We have invented the new cryptographic protocol of universal blind quantum computing (UBQC), demonstrating for the first time the possibility of preserving the privacy of computation using quantum properties. The UBQC has received strong praise (more than 200 joint citations) in the international quantum community as one of the major breakthroughs of the last decade (Vazirani QIP 2010, Aaronson Shtetl-Optimized 2011, Vedral Physics Today 2012, Zeilinger QCMC 2012). In collaboration with experimental lab in Vienna, we also adapted the theoretical work to the optical implementation. Within a week of the publication of the Science paper, more than 50 articles appeared in the international media (including BBC) describing the work as achieving secure quantum cloud computing for the first time. Security as discussed above, is only half the story of a potential quantum era. A more pressing challenge facing any kind of complex system and in particular the emerging quantum technology, is practical verification. We developed a new approach for testing the correctness of any delegated quantum computing based on the ability to compute with encrypted data, while hiding the underlying function. We demonstrated, theoretically and experimentally, that measurement of the randomly prepared single qubits, encrypted from the actual computation, leads to an efficient quantum certification. After our Nature Physics publication, various media (including a live BBC interview), praised the result as a quantum leap in bringing quantum technology closer to reality. We have since been at the forefront of quantum verification, developing a spectrum of various tests using technology available in quantum labs across the world. |
Exploitation Route | We stand at a point in the development of science, technology and business practice where computational models coupled to unprecedented capacity to collect data are becoming vital tools in almost all sectors, from data-driven business models through to in silico modelling of whole biological organisms. At the same time we are seeing the early development of quantum computing devices that offer the capacity to solve problems that are far beyond the limits of classical computation. Our developed verification and validation techniques and novel quantum enhanced secure cloud computing could be explored as a structural understanding of how to use these intermediate quantum systems for scientific and business benefit, contributing to the UK's global leading position in this computational revolution. This could provide the knowledge and expertise to allow the UK science, technology and business and the stakeholders to verify, certify and evaluate today's quantum devices so that we can effectively exploit tomorrow's. |
Sectors | Digital/Communication/Information Technologies (including Software),Security and Diplomacy |