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Mesoscopic Physics Introduction Prof. I.V.Krive lecture presentation Address: Svobody Sq. 4, 61022, Kharkiv, Ukraine, Rooms. 5-46, 7-36, Phone: +38(057)707.

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Presentation on theme: "Mesoscopic Physics Introduction Prof. I.V.Krive lecture presentation Address: Svobody Sq. 4, 61022, Kharkiv, Ukraine, Rooms. 5-46, 7-36, Phone: +38(057)707."— Presentation transcript:

1 Mesoscopic Physics Introduction Prof. I.V.Krive lecture presentation Address: Svobody Sq. 4, 61022, Kharkiv, Ukraine, Rooms. 5-46, 7-36, Phone: +38(057)707 54 30, e-mail:ktf@karazin.ua

2 Testing the Limits of Quantum Mechanics Diffraction of fullerenes in free space T~900-1000 K, excitation energy ~7 eV, 174 vibration degrees of freedom, infrared photons λ~10 μm, Hot, neutral C60 molecules leave the oven, pass through collimating slits, traverse a SiN grating and are detected via thermal ionization by a laser 1.25 m behind the grating

3 Graphene, Graphite, SWNT, Fullerene

4 Atomic Wires of Carbon The atomic chains (up to 16 carbon in a row) have been observed to survive for more than 100 s.

5 Quantum Information Theory Feynman 1982: Simulation of deterministic process on classical computer is “easy”: a*N space for N particles Simulation of random process on classical computer is “difficult”: a N space; exponentially large time/memory required => stochastic algorithms may help Simulation of quantum systems on classical computer is similarly difficult. N spins 1/2 : Evolution is described by unitary matrix in Hilbert space of 2 N dimensions. Stochastic algorithm will not help: Bell’s inequality! Quantum simulator is needed Feynman, Int. J. Theor. Phys. 21, 467 (1982) Deutsch 1985: Quantum complexity can be used to efficiently solve difficult problems; quantum Turing machine Deutsch, Proc. R. Soc. Lond. A 400, 97 (1985) John Bell David Deutsch

6 Requirements (DiVincenzo)  Long decoherence time (10 000 × operation time)  Set of universal gates  Qubit readout  Initialization possibility  Scalability How to build qubit? mIcroscopic two-level systems: atomic/photonic/solid state mAcroscopic: quantum electrical circuits quantum control How is it done?

7 Quantum Bits

8 http://www.chalmers.se/mc2/EN/nobel-symposium-2009/nobel-foundation-s

9 Nobel Prize in Physics 2012 Serge Haroche (right) and assistant Igor Dotsenko (left) at work in the laboratory. David J. Wineland in his laboratory, adjusting a n ultraviolet laser beam used to manipulate ions in a high-vacuum apparatus containing an ion trap. These devices are used to demonstrate the basic operations required for a quantum computer.

10 Cavity QED

11 Measuring and Manipulating Individual Quantum Systems

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15 Innsbruck teleportation machine (R. Blatt)

16 Transmon and cavity QED co-planar wave guide resonator Josephson junctions capacitor & antenna wave guide Flux regime E J >> E C Wallraff et al., Nature 431, 162 (2004)

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18 Quantum Annealer D-Wave's "Quantum“ computers Photograph of a chip constructed by D-Wave Systems Inc., designed to operate as a 128-qubit superconducting adiabatic quantum optimization processor (Quantum Annealer). Simplified schematic of a superconducting flux qubit acting as a quantum mechanical spin. Circulating current in the qubit loop gives rise to a flux inside, encoding two distinct spin states that can exist in a superposition.


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