James H Simons Conference on Quantum and Reversible Computation State University of New York at Stony Brook, 28-31 May 2003 Quantum information and quantum computation has been a rapidly developing field attracting interest from mathematicians, physicists and computer scientists. The goal of this conference is to generate interaction between mathematicians interested in efficient quantum algorithms and quantum error-correcting codes, and physicists trying to build quantum computers. We will stimulate this interaction with lectures on the most important recent developments by world experts. The conference will also cover reversible information processing, which is of interest in classical as well as quantum computing. The reversible nature of the quantum evolution of isolated systems makes logical reversibility on the classical level a prerequisite for any realization of a quantum computer. Reversible computing does not generate the heat associated with information erasure, and is therefore of interest in reducing the heat produced by classical computers. This conference has been made possible through a generous donation by James H Simons. Confirmed speakers: D Averin [SUNY at Stony Brook] I Cirac [Max-Planck-Institute, Munich] M Devoret [Yale University] D DiVincenzo [IBM] E H Farhi [MIT] R Fazio [Scuola Normale Superiore, Pisa] S Han [University of Kansas] M Hillery [Hunter College, CUNY] H K Lo [MagiQ Technologies] L Levitin [Boston University ] J Lukens [SUNY at Stony Brook] C Monroe [University of Michigan, Ann Arbor] L A Orozco [SUNY at Stony Brook] V Semenov [SUNY at Stony Brook] P Shor [AT and T] H Yuen [North West University] P Zoller [Institute for Theoretical Physics, University of Innsbruck] More information and registration can be found on the web at: http://insti.physics.sunysb.edu/itp/conf/simons-qcomputation.html
James H Simons Conference on Quantum and Reversible Computation State University of New York at Stony Brook, 28-31 May 2003 Quantum information and quantum computation has been a rapidly developing field attracting interest from mathematicians, physicists and computer scientists. The goal of this conference is to generate interaction between mathematicians interested in efficient quantum algorithms and quantum error-correcting codes, and physicists trying to build quantum computers. We will stimulate this interaction with lectures on the most important recent developments by world experts. The conference will also cover reversible information processing, which is of interest in classical as well as quantum computing. The reversible nature of the quantum evolution of isolated systems makes logical reversibility on the classical level a prerequisite for any realization of a quantum computer. Reversible computing does not generate the heat associated with information erasure, and is therefore of interest in reducing the heat produced by classical computers. This conference has been made possible through a generous donation by James H Simons. Confirmed speakers: D Averin [SUNY at Stony Brook] I Cirac [Max-Planck-Institute, Munich] M Devoret [Yale University] D DiVincenzo [IBM] E H Farhi [MIT] R Fazio [Scuola Normale Superiore, Pisa] S Han [University of Kansas] M Hillery [Hunter College, CUNY] H K Lo [MagiQ Technologies] L Levitin [Boston University ] J Lukens [SUNY at Stony Brook] C Monroe [University of Michigan, Ann Arbor] L A Orozco [SUNY at Stony Brook] V Semenov [SUNY at Stony Brook] P Shor [AT and T] H Yuen [North West University] P Zoller [Institute for Theoretical Physics, University of Innsbruck] More information and registration can be found on the web at: http://insti.physics.sunysb.edu/itp/conf/simons-qcomputation.html
James H Simons Conference on Quantum and Reversible Computation State University of New York at Stony Brook, 28-31 May 2003 Quantum information and quantum computation has been a rapidly developing field attracting interest from mathematicians, physicists and computer scientists. The goal of this conference is to generate interaction between mathematicians interested in efficient quantum algorithms and quantum error-correcting codes, and physicists trying to build quantum computers. We will stimulate this interaction with lectures on the most important recent developments by world experts. The conference will also cover reversible information processing, which is of interest in classical as well as quantum computing. The reversible nature of the quantum evolution of isolated systems makes logical reversibility on the classical level a prerequisite for any realization of a quantum computer. Reversible computing does not generate the heat associated with information erasure, and is therefore of interest in reducing the heat produced by classical computers. This conference has been made possible through a generous donation by James H Simons. Confirmed speakers: D Averin [SUNY at Stony Brook] I Cirac [Max-Planck-Institute, Munich] M Devoret [Yale University] D DiVincenzo [IBM] E H Farhi [MIT] R Fazio [Scuola Normale Superiore, Pisa] S Han [University of Kansas] M Hillery [Hunter College, CUNY] H K Lo [MagiQ Technologies] L Levitin [Boston University ] J Lukens [SUNY at Stony Brook] C Monroe [University of Michigan, Ann Arbor] L A Orozco [SUNY at Stony Brook] V Semenov [SUNY at Stony Brook] P Shor [AT and T] H Yuen [North West University] P Zoller [Institute for Theoretical Physics, University of Innsbruck] More information and registration can be found on the web at: http://insti.physics.sunysb.edu/itp/conf/simons-qcomputation.html
The conference proceedings will be of interest to physicists, engineers and mathematicians working with quantum mechanical systems and frontier technologies. The QCMC series of conferences provides a forum for the presentation and discussion of new results from the field of quantum information. Quantum information is the study of information stored in quantum systems. The unique properties of quantum mechanics lead to the ability to perform information tasks that are hard or impossible for classical systems.
In the last few years quantum information has played an increasingly central role in the research activities of many scientists within wide ranging areas of physics, mathematics and computer science as it known to be more efficient than its classical counterpart. The impact and advantages of quantum information protocols emerge in numerous situations. In the case of cryptography, quantum dynamics guarantees secure protocols, and in quantum computation, factorization of large numbers, intractable with classical algorithms, can be solved much faster with a quantum computer. It is now widely believed that quantum information will play a leading role in future technologies. Together with the ongoing development of more efficient schemes to solve both new and old tasks in information science, a great deal of interest has been devoted to selecting suitable physical systems where one could realize these ideas. In particular, the quest for large scale integrability has stimulated an increasing interest in the field of solid state physics. Nanoelectronics seems the natural arena to realize physical implementation of quantum hardware. Qubits made out of solid-state devices, such as spins/charges in quantum dots or superconducting nanocircuits, may offer a greater advantage in this respect because fabrication techniques allow for scalability to a large number of coupled qubits. Recent experimental breakthroughs in semiconducting and superconducting nanostructures constitute the first important steps towards the realization of a solid-state quantum computer. In addition the interest in solid state quantum computation has stimulated a large body of research aimed at understanding the properties of entanglement in solid state systems. This Focus issue of New Journal of Physics gathers together contributions from leading experts in the area of solid state quantum information with the aim of providing a panorama of the most exciting scientific questions currently being investigated in the field. Focus on Solid State Quantum Information Contents Quasiparticle entanglement: redfinition of the vacuum and reduced density matrix approach P Samuelsson, E Sukhorukov and M Buttiker Pseudospin quantum computation in semiconductor nanostructures V W Scarola, K Park and S Das Sarma Superconducting qubit network with controllable nearest-neighbour coupling M Wallquist, J Lantz, V S Shumeiko and G Wendin Weak coupling Josephson junction as a current probe: effect of dissipation on escape dynamics J M Kivioja, T E Nieminen, J Claudon, O Buisson, F Hekking and J P Pekola The single Cooper-pair box as a charge qubit K Bladh, T Duty, D Gunnarsson and P Delsing Quantum state transfer in arrays of flux qubits A O Lyakhov and C Bruder Spin filling of a quantum dot derived from excited-state spectroscopy L H Willems van Beveren, R Hanson, I T Vink, F H L Koppens, L P Kouwenhoven and L M K Vandersypen Clauser–Horne inequality for the full counting statistics F Taddei, R Fazio and E Prada Recent advances in exciton based quantum information processing in quantum dot nanostructures H J Krenner, S Stufler, M Sabathil, E C Clark, P Ester, M Bichler, G Abstreiter and J J Finley Spatially highly resolved study of AFM scanning tip-quantum dot local interaction S Kicin, A Pioda, T Ihn, M Sigrist, A Fuhrer, K Ensslin, M Reinwald and W Wegscheider Transfer of entanglement from electrons to photons by optical selection rules M Titov, B Trauzette, B Michealis and C W J Beenakker Non-Abelian Chern-Simons models with discrete gauge groups on a lattice B Doucot and L B Ioffe Landau–Zener transitions in qubits controlled by electromagnetic fields Martijn Wubs, Keiji Saito, Sigmund Kohler, Yosuke Kayanuma and Peter Hänggi Phase-slip flux qubits J E Mooij and C J P M Harmans Mediated tunable coupling of flux qubits Alec Maassen van den Brink, A J Berkley and M Yalowsky Divergent beams of nonlocally entangled electrons emitted from hybrid normal-superconducting structures Elsa Prada and Fernando Sols Decoherence from ensembles of two-level fluctuators Josef Schriefl, Yuriy Makhlin, Alexander Shnirman and Gerd Schön Semiconductor quantum dots for electron spin qubits W G van der Wiel, M Stopa, T Kodera, T Hatano and S Tarucha Rosario Fazio, NEST-INFM and Scuola Normale Superiore, Pisa, Italy
Quantum physics is well known for being counter-intuitive, or even bizarre. Quantum correlations have no equivalence in classical physics. This was all well known for years. But several discoveries in the 1990's changed the world. First, in 1991 Artur Ekert, from Oxford University, discovered that quantum correlations could be used to distribute cryptographic keys. Suddenly physicists realized that quantum correlations and its associated bizarre non-locality, could be exploited to achieve a useful task that would be impossible without quantum physics. What a revolution! And this was not the end. Three years later, Peter Shor, from the AT&T Laboratories, discovered an algorithm that breaks the most used public key crypto-systems. Shor's algorithm requires a quantum computer, yet another bizarre quantum device, a kind of computer that heavily exploits the quantum superposition principle. The following year, in 1995, a collaboration between six physicists and computer scientists from three continents led to the discovery of quantum teleportation, a process with a science-fiction flavour. These discoveries and others led to the emergence of a new science, marrying quantum physics and theoretical computer science, called quantum information science. Today, a steadily growing community of physicists, mathematicians and computer scientists develop the tools of this new science. This leads to new experiments and new insights into physics and information theory. It is a fascinating time. Quantum information is still a very young science. In particular, the technology required to build a quantum computer is still unknown. Only quantum key distribution has reached a certain level of maturity, with a few start-ups already offering complete systems. Nevertheless, quantum information has been widely recognised as a source for truly innovative ideas and disruptive technologies.
The purpose of the conference (the fourth in the series of Vaxjo conferences) was to bring together scientists (physicists, mathematicians and philosophers) who are interested in foundations of quantum physics. An emphasis was made on both theory and experiment, the underlying objective being to offer to the physical, mathematical and philosophic communities a truly interdisciplinary conference as a privileged place for a scientific interaction. Due to the actual increased role of foundations in the development of quantum information theory as well as the necessity to reconsider foundations at the beginning of the new millennium, the organizers of the conference decided that it was just the right time for taking the scientific risk of trying this.
Information is a physical. Physical systems register and process information. These facts generated enormus interest in the development of novel quantum tecnologies, especially because the construction of smaller electronic devices ultimately leads to a consideration of quantum mechanical effects in electronic and computer desingns. The notion of the classical bit of information theory was formally pushed into the realm of the quanta with the introduction of the quantum bit or qubit, in the seminal works of Deutsch (Deutsch, 1985) and Shor (Shor, 1994). They demostrated that, indeed, controlled multipartite qubit interference effects could provide the means for a radical new way of computing, allowing the computation of many intractable computational problems, such as the factoring of large number or exact simulation of large quantum systems. The field of experimental and theoretical research in quantum information and computation has emerged as very important player in the understanding of quantum phenomena the both the basic and technological levels. This has attracted the attention of numerous researchers with backgrounds ranging from computer science, mathematics and engineerin, to the physical sciences, and we now have an interdisciplinary field where great efforts are being made in order to build devices that allow the progressing of information at a quantum level. A concise introduction to the field of quantum information and quantum computation is presented. This stars with the bassic definitions of bits, quantum registers, through to the universal gate-set for building the universal quantum computer, from a quantum network model of computation. The work shows how two-qubit gates suffice for quantum computation, emphasing the power of the quantum circuit representation for entagling and disentagling quantum states. This leads to the “no-cloning theorem”, which leads us to many interesting applications, such as quantum cryptography. Two alternative approaches or performing quantum computation are also described i) the one-way or measurement based quantum computer method, and ii) holonomic or geometric quantum computation. Following this, quantum entaglement quantification is highlighted, particulary its usefulness as a communication resource, in order to describe some of its most celebrated practical applications to date: quantum teleportation, cryptography, dens coding, and data compression. Deutsch’s concept of quantum parallelism is enphasized in order to gain insight into the potential for efficiently solving certain classically intratable algorithms. A subject central to the field of QIP- quantum decoherence- is then introduced.. Possible ways to overcome it, in particular quantum error correction, are discussed. A descriptios of some of the currently available hardware of the practical implementation of quantum computation is provided with a discussion of the main physical quantum bits that are currently employed (or proposed) for a such a purpose.