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The three main themes that will be covered over the week are theory for experimentalists, experimental quantum optics and condensed matter for quantum information processing. A session on each of these will run from 9am-12:30pm, Monday to Friday. Lunch will be followed by free time to enjoy the different activities offered by Burlington Hotel and Sheringham, which include walking, swimming, sailing, golf, putting, tennis, horse riding, bird watching, visiting National Trust Properties and the North Norfolk Steam Railway. The evenings will give Summer School participants time to discuss research areas and problem solve. These discussion times will then be followed by an Industrial Lecture, which will then leave the remainder of the evening once again free to enjoy Sheringham. For more information about the QIP IRC Summer School, please contact qipirc@materials.ox.ac.uk

Abstracts:

Professor Chris Foot (University of Oxford) - Experimental Quantum Physics
Title: Quantum Information Processors Based on Optical Lattices
Abstract: Optical lattices are made by the interference of light beams to create a periodic potential that can confine atoms, e.g. a standing wave formed by two counter-propagating laser beams can  confine atoms in a regular one-dimensional array along the axis of the beams. Optical lattices containing one, or more, atoms per lattice site can be achieved by loading atoms into the optical lattice from a Bose-Einstein condensed cloud of ultra-cold atoms produced in a magnetic (or dipole-force) trap.  The interaction between atoms and the light that leads to the formation of the optical lattice will not be described in detail [see Foot, 2005]; the light perturbs the atomic energy levels by an amount proportional to the intensity of the light (and spontaneous is negligible on the timescale required for experiments).  The Bose-Einstein condensate behaves as a superfluid in the magnetic trap and also in a weak optical lattice where there is tunnelling between the potential wells. The important features of optical lattices for QIP, covered in the lecture, are:  

(a) Mott-insulator transition 
As the depth of the potential wells in an optical lattice increases, atoms undergo a quantum phase transition from a superfluid to a Mott-insulator phase. It is intuitively obvious that deep wells have little quantum tunnelling between and so the number of atoms at each site remains constant; however a crucial feature of the Mott-insulator phase is that a state can be prepared that has a high probability of exactly one atom per optical lattice site, i.e. 1 atom, not 0, 2 or more. A regular array of atoms prepared in this way, in the lowest vibrational level of the optical lattice, can be regarded as a quantum register of many qubits initialized in the state required for QIP. 
(b) Implementation of a quantum gate 
A phase gate for cold atoms can be made by physically bringing two atoms together so that they interact for a short time. If these controlled collisions are carried out such that different states of the qubit (atom) accumulate different phases then the interaction leads to a phase gate. The interactions between neutral atoms are short range, c.f. the Coulomb interaction between ions, hence such gates operate relatively slowly. 
(c) Addressing individual qubits and their read out 
Experiments carried out so far with standing waves of infra-red radiation have a spacing between potential wells of 0.4 microns (1/2 the wavelength of the light) so that atoms cannot be detected individually. Experimental work at Oxford is directed towards solving this problem; by using diffractive optical elements we can create light fields with arbitrary intensity distributions, e.g. an array of spots (intensity maxima) where the position of each spot can be independently controlled.  This flexibility allows the creation of a two-dimensional lattice in which the spacing can be adjusted from a few microns to a larger spacing for which the individual atoms can be resolved optically (or other more complex configurations). 
Direct quantum simulation and universal quantum simulation 
“Richard Feynman is often credited with first highlighting the power of quantum information processing by observing that quantum systems are impossible to simulate efficiently using classical means. One corollary of this is that quantum systems have remarkable information  processing capabilities, which has led to the development of quantum algorithms.  A second and less well-studied corollary is that quantum systems can efficiently simulate other quantum systems” [from Cummins and Jones, 2000].  Thus a quantum computer can simulate any quantum system and can be called a Universal Quantum Simulator (UQS). 
This statements applies to lattice-based processors, however optical lattices can be configured to simulate condensed matter systems more directly, e.g. interacting spins on a lattice.  Such direct quantum simulation (DQS) does not require such high fidelity as the implementation of a quantum error correction, for example, and therefore it is realistic to expect that DQS of two- and three-dimensional lattices, that are of interest to condensed-matter physicists, can be achieved within the next few years. 
Other important applications of optical lattices include: (i) Atomic clocks. Atoms confined in sparsely-filled optical lattices do not undergo collisions which are the major limitation in present-day atomic clocks, however the light shift (a.c. Stark effect) associated with the confinement cause uncertain perturbations to the transition frequency. There are various schemes for overcoming this that should lead to better future timekeeping. (ii) Storage of quantum information. The phenomenon of so-called slow, or stopped, light that arises when radiation interacts with an atomic medium has been proposed as a means of storing and retrieving quantum information. Using atoms in an optical lattice would give long storage times for the same reasons as in application (i); a long decoherence time gives a narrow transition. 
References: 
Foot, C J. Atomic Physics. OUP, 2005 
Cummins, H & Jones, J A. NMR magnetic resonance: a quantum technology for computation and spectroscopy. Contemporary Physics, 41, 383 (2000) 
D Jaksch. Optical lattices, ultracold atoms and quantum information processing. Contemporary Physics, 45, 367 (2004)

Dr Jens Eisert (Imperial College) - Theory for Experimentalists
Title of first lecture: Quantum information 101
Absract: This first tutorial will be concerned with the basics of quantum information theory: What is a quantum state and a qubit? Is quantum information different from classical information? What are impossible machines? Cloning and teleportation, elements of entanglement theory.
Title of second lecture: Continuous-variable quantum information processing
Abstract: The study of quantum information processing based on quantum systems with canonical coordinates has seen an enormous progress in recent years, both from a theoretical as well as from an experimental perspective. This tutorial provides an elementary introduction to quantum information theory over continuous variables, emphasising the theory of entanglement in such quantum systems. Further developments are outlined.

Dr Andrew Shields (Toshiba Cambridge Research Laboratory) - Industrial Lecture
Title: Single Photon Technology for Secure Communications
Abstract: Quantum optics may soon allow unconditionally secret communication to be realised.  I will discuss recent progress in our lab to develop a practical system for quantum key distribution on optical fibres based on weak coherent pulses.  The performance of current systems is limted by today's photon generation and detection technologies.  New types of quantum dot based single photon detector could dramatically enhance secure bit rate enabling new applications.  The development of a fibre compatible single photon source is important for extending the range and bit rate of unconditionally secure quantum key distribution, as well as being an essential component in future quantum networks.   

Professor Andrew Steane (University of Oxford) - Experimental Quantum Optics
Title: Ion Trap Quantum Computing 1 & 2
Abstract: The lectures will be aimed at a quantum information audience not necessarily working with, or preparing to work with, ion traps, but who wish to gain some familiarity.  I will summarise the main experimental methods and issues for implementing quantum computing by laser manipulation of trapped ions.   

Professor John Jefferson (Qinetiq) - Industrial Lecture
Title: Exchange of quantum information between static and propagating spin-qubits in quantum wires
Abstract: An appealing demonstration of the transfer of quantum information would be a system in which the spin of a bound electron interacts with the spin of a propagating electron, transferring quantum information betwen the two.  In this lecture I will explain how such a system can be realised in a semiconductor quantum wire or a carbon nanotube.  Even the possibility of such a system poses a number of fundamental qustions such as: what is the origin and nature of the interaction between the spins?  How does this lead to exchange of quantum information and how may this be controlled?  How do we ensure that only two electrons are involved with one bound and the other unbound?  What is the role of charge and orbital motion of the electrons?  How are the spins initialised and measured?  What are the technological challenges in realising such a system?  I will address these questions and outline the spin-dependent scattering theory from which the transfer of quantum information and generation of entanglement may be understood. 

Professor John Rarity (University of Bristol) - Experimental Quantum Optics
Title: Photonic Quantum Logic
Abstract: In this lecture I will introduce the concept of coding data bits in the phase or polarisation state of single photons thus creating quantum bits (qubits). This then allows us to exploit wave particle duality for novel computing and communication protocols. The first practical application is the fibre and free-space quantum cryptography apparatus used for secure exchange of keys [1,2]. I will briefly review progress in this area focussing on free space experiments.
Further developments such as quantum relays and other few qubit applications require that pairs of qubits interact. To avoid the inevitably weak non-linear interactions between photons conditional linear optics logic has been developed. This has allowed the demonstration of the simplest quantum gate, the quantum conditional NOT (CNOT) [3,4].
Optical quantum logic schemes require high efficiency sources of single photons and entangled photon pairs. I will describe how these components are being optimised by wavelength scale engineering of optical structures. In the future we would also want non-linearity at the single photon level which may be achievable in wavelength scale structures.
[1] N. Gisin, G. Ribordy, W. Tittel and H. Zbinden Rev. Mod. Phys. 74, 145 (2002).
[2] C. Kurtsiefer, et al, Nature 419, 450 (2002).
[3] J.G.Rarity, Roy. Soc. Phil. Trans. 361, 2003, 1507-18
[4] J.L. O'Brien et al, Nature 426, 264 (2003).   

Dr Pieter Kok (Hewlett Packard Bristol Research Laboratory) - Theory for Experimentalists
Title: Entanglement-Enhanced Quantum Measurements
Abstract: A discret variable (such as a qubit) can in principle be read with perfect fidelity, but this is not true for continuous variables, such as the phase of a field.  We therefore need to establish limits on the precision with which we can estimate a continuous variable.  In these lectures, I will derive some bounds on the precision of a phase measurement, and show that there are two different bounds that are relevant.  The question is then which bound applies to which physical situation.
Another way of thinking about these bounds is in terms of the "Standard Quantum Limit" (SQL) or the "Heisenberg Limit" (HL).  Contrary to what its name suggests, the SQL is typically regarded as a classical limit to phase measurements.  The reason for this is that to reach the Heisenberg Limit, we need to use macroscopic superpositions, often in the form of entanglement.  I will give several examples of this, and show how these techniques can be used for enhancing frequency standards, clock synchronisation and (sub-Rayleigh resolution) quantum lithography.

Dr Konrad Banaszek (Nicolaus Copernicus University, Poland) - Experimental Quantum Optics
Title: Experimental Quantum Optics
Abstract: One of the prerequisites in applied quantum information processing is the ability to generate, control, and characterise single quantum systems.  For optical radiation, these tasks have been extensively studied in quantum optics bringing experimental advances that are now routinely used in quantum information science.  These lectures will review some of the basic concepts and techniques developed in quantum optics with their applications to quantum information processing. 

Dr Dan Browne (University of Oxford) - Theory for Experimentalists
Title: Entanglement generation via conditional photon-emission, interfernce and detection
Abstract:  Entangled states form a key resource in quantum information science, being a prerequisite for quantum teleportation and certain quantum cryptography and computation proposals. In particular so-called "Bell-states" - maximally entangled two-qubit states - have a wide range of applications.  In this lecture, I will review various proposals for entangling matter qubits via photon emission, interference and detection. The schemes all share common features. The matter qubits are driven such that photons are emitted conditional on the qubits' states. The photon(s) are then detected in such a way that "which-path" information as to the origin of the photon is lost. This "erasure" of which-path information is usually performed by splitting or mixing the photons on a beam splitter. The effect of the detection is to realise, with a certain probability, an "entangling measurement" on the matter qubits, which can, for example, generate a Bell state between the matter qubits. I will review various proposals based on this principle and discuss their respective advantages.  If time allows I will also discuss a further application of such "entangling measurements", namely the generation of graph states. These are multi-qubit entangled states which are a resource for "one-way quantum computation".