January 12, 2012:
Quantum Theory of the Classical
by Wojciech Zurek, Los Alamos National Laboratory, USA 

January 12, 2012:
Experimental Quantum Error Correction
by Raymond Laflamme, IQC, Waterloo, Canada 

Feb 9, 2012:
Carbon Spintronics
by Guido Burkard,University of Konstanz, Germany 

Mar 08, 2012:
Breaking the bounds of quantum thermodynamics
by Gershon Kurizki, Weizmann Institute of Science, Israel 

May 24, 2012:
Simulating quantum transport with atoms and light
by Philippe Bouyer, Laboratoire Charles Fabry, France 

July 26, 2012:
Doing small systems: Fluctuation relations and the arrow of time
by Peter Hanggi, University of Augsburg, Germany 

August 2, 2012:
The evasive cheshire cat: How to detect fractional statistics
by Yuval Gefen, Weizmann Institute of Science, Israel 

September 6, 2012:
Generating and exploiting intense attosecond pulses
by Dimitris Charalambidis, University of Crete and Institute of Electronic Structure and Laser (IESL), FORTH 

October 25, 2012:
Singleatom spin qubits in silicon
by Andrea Morello, The University of New South Wales, Australia 

November 29, 2012:
Fluctuoscopy of Superconductors and Dynamics of Abrikosov’s Lattice Formation Close to Hc2(0)
by Andrey Varlamov, Institute of Superconductivity and Innovation Materials (SPINCNR), Italy 

December 7, 2012:
CQT Annual Symposium 2012  The Famous, The Bit and The Quantum
Randomness by Avi Wigderson, Institute for Advanced Study, Princeton, USA Quantum Technology for a Networked World by Peter Knight, Imperial College, UK 

Date: 12 January 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Wojciech Zurek, Los Alamos National Laboratory, USA
Media: Video
I discuss three insights into the transition from quantum to classical. I will start with (i) a minimalist (decoherencefree) derivation of preferred states. Such pointer states define events (e.g., measurement outcomes) without appealing to Born's rule. Probabilities and (ii) Born’s rule can be derived from the symmetries of entangled quantum states. With probabilities at hand one can analyze information flows from the system to the environment in course of decoherence. They explain how (iii) robust “classical reality” arises from the quantum substrate by accounting for objective existence of pointer states of quantum systems through redundancy of their records in the environment. Taken together, and in the right order, these three advances elucidate quantum origins of the classical.*
*W. H. Zurek, Nature Physics 5, 181188 (2009).
Date: 12 January 2012, 5.30pm
Venue: CQT Seminar Room, S150315
Speaker: Raymond Laflamme, IQC, Waterloo, Canada
Media: Video
The Achilles' heel of quantum information processors is the fragility of quantum states and processes. Without a method to control imperfection and imprecision of quantum devices, the probability that a quantum computation succeed will decrease exponentially in the number of gates it requires. In the last fifteen years, building on the discovery of quantum error correction, accuracy threshold theorems were proved showing that error can be controlled using a reasonable amount of resources as long as the error rate is smaller than a certain threshold. We thus have a scalable theory describing how to control quantum systems. I will briefly review some of the assumptions of the accuracy threshold theorems and comment on recent experiments that have been done and should be done to turn quantum error correction into an experimental reality.
Date: 09 February 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Guido Burkard, Department of Physics, University of Konstanz, Germany
Media: Video
Carbon, in the form of graphene and carbon nanotubes, has recently emerged as an interesting alternative material for electronics. Here, we argue that carbon is also a unique material for a new type of electronics that is based on the electron spin rather than its charge, known as spintronics, and in particular for spinbased quantum computing [1]. Due to the low concentration of nuclear spins and relatively weak spinorbit coupling, carbonbased structures allow for long coherence times, which is the primary figure of merit for the quality of a spin quantum bit (qubit). We discuss the formation of quantum dots, acting as electron “traps’’, in graphene and their potential use for quantum information processing. In diamond, the spin coherence of defect centers can persist even at ambient temperatures. After introducing this fascinating quantum system, we briefly present a particular mechanism for storing and retrieving quantum information in an atomic nucleus in diamond [2].
[1] B. Trauzettel, D. Bulaev, D. Loss, and G. Burkard, Nature Phys. 3, 192 (2007).
[2] G. D. Fuchs, G. Burkard, P. V. Klimov, and D. D. Awschalom, Nature Phys. 7, 789 (2011).
Date: 08 March 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Gershon Kurizki, Weizmann Institute of Science, Israel
I shall revisit the traditional formulation of the three laws of thermodynamics and the bounds they imply on thermodynamic observables , and argue that all of these have to be modified and reformulated when the system is enacted upon on time scales shorter than the bath memory time. Practical consequences related to work extraction and cooling will be demonstrated to be in stark contrast with existing schemes .
Date: 24 May 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Philippe Bouyer, Laboratoire Charles Fabry, France
The transport of quantum particles in non ideal material media (eg the conduction of electrons in an imperfect crystal) is strongly affected by scattering from impurities of the medium. Even for a weak disorder, semiclassical theories, such as those based on the Boltzmann equation for matterwaves scattering from the impurities, often fail to describe transport properties and full quantum approaches are necessary. The properties of the quantum systems are of fundamental interest as they show intriguing and nonintuitive phenomena that are not yet fully understood such as Anderson localization, percolation, disorderdriven quantum phase transitions and the corresponding Boseglass or spinglass phases. Understanding quantum transport in amorphous solids is one of the main issues in this context, related to electric and thermal conductivities.
Ultracold atomic gases can now be considered to revisit the problem of quantum conductivity and quantum transport under unique control possibilities. Dilute atomic BoseEinstein condensates (BEC) and degenerate Fermi gases (DFG) are produced routinely taking advantage of the recent progress in cooling and trapping of neutral atoms. Transport has been widely investigated in controlled potentials with no defects, for instance periodic potentials (optical lattices). Controlled disordered potentials can also be produced with various techniques such as the use of magnetic traps designed on atomic chips with rough wires, the use of localized impurity atoms, the use of radiofrequency fields or the use of optical potentials. This recently lead to the observation of the Anderson Localization of a BEC in 1D and 3D,and the study of diffusion properties during matterwave transport.
Date: 26 July 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Peter Hanggi, University of Augsburg
This talk is aimed at highlighting issues that relate of doing thermodynamics and statistical physics of finite size systems. This theme gained considerable importance in view of fascinating advances in nanotechnology and system biology. While the fathers of thermodynamics developed the famous 5 Laws of Thermodynamics (incl. a “–1_Law), having in mind macroscopic systems, these grand concepts need to be inspected anew in view of the fact that the fluctuations grow with decreasing size to a level where they even may play the dominant role. This holds true particularly for the interrelationships between fluctuations and, importantly, the measurements of work, heat & heat flow and thermodynamic equilibrium quantifiers such as (nonfluctuating) free energy changes or production of thermodynamic entropy.  Subtleties occur in equilibrium thermodynamics for small systems, such as the role of finite size for quantities like (possibly negativevalued) canonical heat capacitance in presence of strong systemenvironment coupling.
I further elaborate on recent, timely results for nonequilibrium classical and quantum fluctuation relations. An attempt is made to outline pitfalls and still open issues (relativistic and others) together with those inherent difficulties that likely do emerge with the experimental validation scenarios of such relations. Finally, a connection between Fluctuation Relations, nonlinear Response and its feasible relation with the everlasting intriguing challenge in detecting the origin of an "Arrow of Time" will be elucidated.
This presentation is based on joint work with Michele Campisi, GertLudwig Ingold and Peter Talkner, all at the University of Augsburg.  Own pertinent recent works that apply for the theme of this talk are:
[1] G. L. Ingold, P. Hänggi, and P. Talkner
Specific heat anomalies of open quantum systems
Phys. Rev. E 79, 061105 (2009)
[2] M. Campisi, P. Hanggi, and P. Talkner
Colloquium: Quantum fluctuation relations: Foundations and applications
Rev. Mod. Phys. 83, 771791 (2011);
Addendum and Erratum: Quantum fluctuation relations: Foundations and applications
Rev. Mod. Phys. 83, 1653 (2011).
[3] M. Campisi and P. Hanggi
Fluctuation, Dissipation and the Arrow of Time
Entropy 13, 20242035 (2012).
Date: 2 August 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Yuval Gefen, Weizmann Institute of Science
Certain strongly correlated electronic systems give rise to quantized low energy excitations which possess fractional statistics. A number of protocols to detect such quasi particles—anyons have been proposed in recent years, yet the quest for fractional statistics has not resulted in an unequivocal manifestation. I will review some of theoretical proposals for detection of anyons, and discuss why it is so difficult to find them.
Date: 6 September 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Dimitris Charalambidis, University of Crete and Institute of Electronic Structure and Laser (IESL), FORTH
During the last decade we have systematically developed methods and instrumentation leading to the coherent emission of intense XUV pulses of subfemtosecond duration. As a measure of the term "intense" we identify the feasibility in inducing observable nonlinear processes solely by the XUV radiation. Nonlinear XUV processes are essential in (a) attosecond pulse metrology, (b) XUVpumpXUVprobe studies of ultrafast dynamics, (c) reaching highest spatiotemporal resolution and d) exploring new physics in innershell nonlinear or even strong field processes. We regard the above as current and future main steam developments in attoscience.
I will review the physics and technology behind intense attosecond pulse train [1,2] and coherent XUV supercontinuum [3] generation, as well as recent XUVpumpXUVprobe studies at the boundary between fempto and attosecond scales [4].
Date: 25 October 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Andrey Morello, ARC Centre of Excellence Centre for Quantum Computation and Communication Technology, The University of New South Wales
The idea of using the spin of a single donor atom in silicon to encode quantum information goes back to the Kane proposal [1] in 1998. The proposal was motivated by two observations: (i) Silicon is one of the most promising materials to host spin qubits in solid state, owing to the very weak spinorbit coupling, and to the possibility to eliminate decoherence from nuclear spins by isotopic purification; (ii) A trilliondollar worth industry already exists, that has developed extraordinary tools to manufacture silicon nanoscale devices in a reliable and costeffective way.
The proposal appeared ambitious, visionary but very challenging at the time, because it relied upon the nontrivial assumption that the progress in the fabrication of classical silicon devices could be harnessed to pursue quantum information goals. Indeed, over a decade of intense efforts has been necessary before the first breakthroughs in silicon quantum technologies could be demonstrated.
I will present the first experimental demonstration of a qubit based on a single phosphorus atom in silicon. The atom is coupled to a silicon SingleElectron Transistor, and the whole device is fabricated retaining standard CMOS technologies such as ion implantation [2] and metal gates fabricated on top of highquality silicon oxide [3].
In a singleatom device, we have demonstrated singleshot readout [4] and coherent control [5] of the donor electron spin, as well and the spins of the 31P nucleus and of a stronglycoupled 29Si nucleus. All three qubits exhibit excellent coherence and highfidelity readability, with the nuclear ones being accessible through a quantum nondemolition measurement.
These results represent major milestones in the search for a scalable and coherent quantum computer platform, and confirm the vision of silicon as the choice material for both quantum and classical technologies.
[1] B. E. Kane, Nature 393, 133 (1998).
[2] D. N. Jamieson et al., Appl. Phys. Lett. 86, 202101 (2005).
[3] A. Morello et al., Phys. Rev. B 80, 081307(R) (2009).
[4] A. Morello et al., Nature 467, 687 (2010).
[5] J. J. Pla et al., Nature (2012), in press.
Date: 29 November 2012, 4pm
Venue: CQT Seminar Room, S150315
Speaker: Andrey Varlamov, Institute of Superconductivity and Innovation Materials (SPINCNR), Italy
I start my lecture from qualitative discussion, based on the Heisenberg principle, of the nature of thermal fluctuations in superconductor at temperatures above the critical one. Then the analogous consideration is applied to the regime of quantum fluctuations at zero temperature above the field Hc2(0). Basing both on microscopic and qualitative analysis we demonstrate, that here, fluctuating Cooper pairs rotating in magnetic field present themselves precursor images of Abrikosov’s vortices and form the clusters with specific superconducting features. I evaluate both the characteristic size QF( H) and lifetime QF( H) of such formations. When magnetic field reaches Hc2(0) from above the size and lifetime of such clusters tend infinity and the order, corresponding Abrikosov’s lattice is established. In second part of the lecture I discuss fluctuoscopy  the method of investigation of intrinsic properties of superconductors by means of the detailed analysis of their fluctuation magnetoconductivity, tunneling characteristics, Nernst coefficient throughout the phase diagram.