Quantum Computation

Quantum Artificial Intelligence Laboratory (QuAIL) @ NASA, Ames

Research Type: 
Theory
Experiment
Leader: 
Andre G. Petukhov, Eleanor G. Rieffel

Quantum computations on a topologically encoded qubit

Date: 
2016-06-07
Author(s): 

D. Nigg, M. Müller, E. A. Martinez, P. Schindler, M. Hennrich, T. Monz, M. A. Martin-Delgado, R. Blatt

Reference: 

Science 345, 302 (2014)

The construction of a quantum computer remains a fundamental scientific and technological challenge because of the influence of unavoidable noise. Quantum states and operations can be protected from errors through the use of protocols for quantum computing with faulty components. We present a quantum error-correcting code in which one qubit is encoded in entangled states distributed over seven trapped-ion qubits. The code can detect one bit flip error, one phase flip error, or a combined error of both, regardless on which of the qubits they occur.

Quantum Technologies: Implications for European Policy

Summary: 

The Joint Research Centre, the European Commission's in-house science service, has published a Science for Policy report on Quantum Technologies.

At the Amsterdam conference the Joint Research Centre (JRC) Deputy Director General Maive Rute announced at the Amsterdam Conference on Quantum Technologies, an issue paper titled "Quantum Technologies: Implications for European Policy".

Calarco/Bolle: new cooperation models are needed to bridge the "valley of death"

Summary: 

Prof. Tommaso Calarco, Institute of Complex Quantum Systems, and Michael Bolle, President of R&D, Robert Bosch GmbH, argue that new cooperation models are needed to bridge university research and industry.

In today's blog post of Commissioner Oettinger features the discussion between prof. Tommaso Calarco, Institute of Complex Quantum Systems, and Michael Bolle, President of R&D, Robert Bosch GmbH, concerning the need of new cooperation models to bridge the "valley of death".

Russian Quantum Center (RQC)

Website: 
Research Type: 
Theory
Experiment

About Us

 
On December 14, 2010, the Russian Innovation Hub Skolkovo announced the selection of its first 16 resident projects. Certificate No. 13 was awarded to the project "International Center for Quantum Optics and Quantum Technologies" - the Russian Quantum Center (RQC). This day can be considered the official birthday of the RQC.
 
Leader: 
Ruslan Yunusov

NanoSciences and Atom-Technology

Website: 
Research Type: 
Theory
Experiment

Quantum Information Processing and Communication

Contribution from CEMES CNRS UPR 8011

Updated on 29-Apr-16

Activity summary

CEMES is developing quantum technology based on a dual approach using (1) single molecular design and atom manipulation on surfaces to create quantum circuits and logic gates and (2) plasmonic circuits and modal logic gates coupled to single photon sources (QIPC 4.2[1]). By a combined theoretical and experimental effort sustaining both approaches, CEMES aims at downsizing quantum information processing and communication to devices with footprint as small as 1 nm2 and interconnects as narrow as 1 nm, a formidable challenge for miniaturizing the mainstream QIPC paradigms (qubits or trapped atoms). Quantum control in a nanometer-scale single molecule or atom circuits is achieved by manipulating electronic quantum states by the presence of adatoms in order to implement quantum logic gates and, in the longer term, by using single molecule latching (QIPC 4.2, 4.3.1). Quantum computing is explored with magnetic molecular qubits but also with a range of qubit-free atomic-scale quantum systems using the new Quantum Hamiltonian Computing approach. With quantum plasmonics, optical qubits, namely colored centers in nanodiamonds, are coherently coupled through a delocalized quantum plasmonic mode sustained by crystalline plasmonic structures (QIPC 4.1.2-4.1.5). Such architectures are implemented to investigate and minimize the decoherence-dissipation link and allow the emergence of superposition states in an entanglement regime, which could be used for the design of single photon transistors and substrate-borne optical quantum logic gates. Both approaches offer ways to long range transfer quantum information and correlate quantum states through atomic-scale quantum channels such as molecular wires, atom wires or single plasmon waveguides (QIPC 4.1.2 - 4.1.5). The dual nature of plasmon modes (electron-photon) offers an opportunity to interface electronic and optical quantum computing and quantum information transfer devices. It also provides a way to reach larger bandwidth for the study of quantum dynamics. On the other hand, the quantum-classical and classical-quantum conversion is studied at the input and output of atom circuits or single molecule logic gates to exploit quantum decoherence instead of avoiding it (QIPC 4.3.4, 4.5). Finally, theory of the control and coherence of state space trajectory, complex logic gate design, zero effective mass tunneling, and quantum plasmonics description is carried out (QIPC 4.3).

Detailed expertise

1. Quantum control theory (QIPC 4.3)

Theory : Trajectory in state space. Decoherence and trajectory control by modifying the Hamiltonian generating the quantum evolution on the Bloch hypersphere. Quantum control robustness.

References :
- A quantum digital half adder inside a single molecule. I. Duchemin and C. Joachim, Chem. Phys. Lett., 406, 167 (2005).
- The driving power of the Quantum superposition principle for molecule-machine. C. Joachim, J. Phys., Cond. Mat., 18, S1935 (2006).
- An intramolecular digital ½ adder with a tunneling current drive and reads out. I. Duchemin, N. Renaud and C. Joachim, Chem. Phys. Lett., 452, 269 (2008).
- The design & stability of NOR and NAND logic gates constructed with 3 quantum states. N. Renaud and C. Joachim, Phys. Rev. A, 78, 062316 (2008).

 

2. Qubit-based quantum computing  (QIPC4.2.6)

Experimental : Synthesis and spectroscopy probing of a molecule-SWAP

Theory : Design of intramolecular qubits in complex multicenter mixed-valence compounds.

Reference :
A controlled Quantum SWAP logic gate in a 4-Center metal complex. M. Hliwa, J. Bonvoisin and C.Joachim. In “Architecture & Design of Molecule Logic Gates and Atom Circuits”, Springer Series: Advances in Atom and Single Molecule Machines: Vol. II, p. 237 (2013), ISBN 978-3-642-33136-7

 

3. Qubit-free quantum computing (New section QIPC 4.2.7 ? (exp.), 4.3.1 (theor.))

Quantum atom circuits: Implementation of a NOR gate with 10 dangling bonds on Si(100)H surface. Design of all 2-inputs, 1-output Boolean logic gates. Bistable molecules as logic input.

References :
- Realization of a Quantum Hamiltonian Computing Boolean logic gate on the Si(001):H surface. M. Kolmer, R. Zuzak, S. Godlewski, M. Szymonski, G. Dridi, C. Joachim. Nanoscale, 7, 12325 (2015).
- Mechanical conformation  switching of a single pentacene molecule on Si(100)-2x1. O.A. Neucheva, F. Ample and C. Joachim, J. Phys. Chem. C, 49, 117 (2013).

Quantum molecular logic gates: Manipulation of electronic states in a single molecule by using single Au atoms as inputs. Implementation of a NOR, a XOR gate and an analogic adder.

References :
-Manipulating molecular quantum states with classical metal atom inputs : demonstration of a single Molecule NOR logic gate. W.H. Soe, X. Manzano, N. Renaud, P. De Mandoza, A. De Sarkar, F. Ample, M. M.Hliwa, A.M. Echevaren, N. Chandrasekhar and C. Joachim, ACS Nano,5 ,1436 (2011).
- A single molecule NOR gate with Au atom inputs. W.H. Soe, X. Manzano, N. Renaud, P. De Mandoza, A. De Sarkar, F. Ample, M. Hliwa, A.M. Echevaren, N. Chandrasekhar, C. Joachim, Phys. Rev. B, 83, 155443 (2011).
- Manipulation of a single molecule ground state by means of gold atom contacts. C.Manzano, W.H. Soe , M. Grisolia, M. Hliwa and C.Joachim, Chem. Phys. Lett, 587, 35 (2013).
- Large starphene single molecule NOR Boolean logic gate. C. Manzano, W.H. Soe, P. de Mandoza, PR. McGonical, A.M. Echavaren and C. Joachim, Chem. Phys. Lett., (2016) submitted.

Quantum plasmonic logic gates: Implementation of multiple input/output reconfigurable logic gates in confined 2D plasmonic architectures for high speed bosonic transfer functions at room temperature. The quantum plasmonic state is populated from a quantum photon source.

References :
- Plasmonic Purcell factor and coupling efficiency to surface plasmons. Implications for addressing and controlling optical nanosources. G Colas des Francs, J Barthes, A Bouhelier, J C Weeber, A Dereux, A Cuche and C Girard, J. Opt. 18 (2016) in press. (Special issue on Quantum plasmonics)
- Near-field hyperspectral quantum probing of multimodal plasmonic resonators
A. Cuche, M. Berthel, U. Kumar, A. Drezet, S. Huant, E. Dujardin, C. Girard, G. Colas des Francs. 2016, submitted
- Reconfigurable modal Boolean logic gates inside a single plasmonic cavity, U. Kumar, S. Viarbitskaya, C. Girard, A. Cuche, A. Bouhelier, E. Dujardin, 2016, submitted

Theory : Quantum graph theory applied to the design of bollean logic gates. Quantum Hamiltonian Computing so far up to a 2x2 bit adder with carry.

References:
- Classical Boolean Logic gates with Quantum System. N. Renaud and C. Joachim, J. Phys. A, 44, 155302 (2011).
- Quantum Design rules for single molecule logic gates. N. Renaud, M. Hliwa et C. Joachim, Phys. Chem. Chem. Phys., 13, 14404 (2011).
- The different designs of molecule logic gates. C. Joachim, N. Renaud and M. Hliwa, Adv. Materials, 24, 312 (2012).
- The mathematics of a QHC ½ adder Boolean logic gate. G. Dridi, R. Julien, M. Hliwa, C. Joachim, Nanotechnology, 26, 344003 (2015).

 

4. Quantum communication in complex circuits (QIPC 4.1.2 to 4.1.5)

Experimental : 2D plasmon mode design for long distance quantum information transfer and modal logic gate implementation. Decoherence control and coupling of single photon source to single plasmon for plasmon-mediated long distance entanglement. Quantization of plasmon in nanoscale 1D channels for quantum information transfer.

Super tunneling; long distance state correlation through an atomic scale quantum channel: atom wire, low effective mass molecular wires. Very long distance tunneling for quantum information exchange in complex quantum computing structures. Modulation of the long-range intramolecular spin-spin entanglement with the magnetic molecular orbital topology.

References:
- Conductance of a single flexible molecular wire composed of alternating Donor and Acceptor units. C.Nacci, F. Ample, D. Bleger, S. Hecht, C. Joachim and L. Grill, Nature Comm., 6, 7397 (2015).
- Electronic and magnetic communication in mixed-valent and homovalent ruthenium complexes containing phenylcyanamide type bridging ligands. M. Fabre, J. Bonvoisin. JACS. 129, 1434 (2007)
- Manipulating and squeezing the photon density of states with plasmonic nanoparticle networks. C. Girard, E. Dujardin, R. Marty, A. Arbouet, G. Colas des Francs. Phys Rev. B., 2010, 81, 153412
- Tailoring and imaging the plasmonic local density of states in crystalline nanoprisms. S. Viarbitskaya, A. Teulle, R. Marty, J. Sharma, C. Girard, A. Arbouet and E. Dujardin. Nature Materials, 2013, 12, 426-432.
- Multimodal plasmonics in fused colloidal networks A. Teulle, M. Bosman, C. Girard, K. L. Gurunatha, M. Li, S. Mann, E. Dujardin. Nature Materials, 2015, 14, 87-94
- Near-field hyperspectral quantum probing of multimodal plasmonic resonators. A. Cuche, M. Berthel, U. Kumar, A. Drezet, S. Huant, E. Dujardin, C. Girard, G. Colas des Francs. 2016, submitted
- Modulated information transfer though delocalized plasmon mode engineering. U. Kumar, S. Viarbitskaya, C. Girard, A. Cuche, A. Bouhelier, E. Dujardin, 2016, submitted

Theory : Complex value band theory, zero effective mass in tunnelling regime. Entangled states in Hilbert space.

References:
- Conductance decay of surface Hydrogen tunnelling junction fabricated along a Si(100)-(2x1)H atomic wire. H. Kawai, Y.K. Yeo, M. Saeys and C. Joachim, Phys. Rev. B, 81, 195316 (2010).
- Si(100)H surface Dangling bond atomic wire enginnering. M. Kepenenkian, R. Robles, C. Joachim and N. Lorente, NanoLett. 13, 1192 (2013).

5. Atom Technology (QIPC 4.3.4 & 4.5)

Experimental : Atom-by-atom construction of Boolean quantum Hamiltonian logic gates at a semi-conductor surface with the low-temperature, UHV 4 probe STM in CEMES PicoLab.

References:
-Atomic scale fabrication of dangling bond structures on hydrogen passivated Si(001) wafers processed and nanopackaged in a clean room environment. M. Kolmer, S. Godlewski, R. Zuzak, M. Wojtaszek, C. Rauer, A. Thuaire, J.M. Hartmann, H. Moriceau, C. Joachim and M. Szymonski,, Appl. Surf. Sci., 288, 83 (2014)
- Imaging Single atom contact and single Atom manipulation at Low Temperature using the new ScientaOmicron LT-UHV 4 STM. J. Yang, D. Sordes, M. Kolmer, D. Martrou and C. Joachim, Eur. J. Phys. AP, 73, 10702 (2016).

Theory : Classical-quantum and quantum-classical conversion theory for atomic or molecular circuit input/output. Band structure optimization for metallic nanopads and pointer states.

References :
- A time-dependant approach to electronic transmission in model molecular junctions. N. Renaud, M. Ratner and C. Joachim, J. Phys. Chem. B, 115, 5582 (2011).
- Contact conductance of a graphene nanoribbon with its graphene Nano-electrodes. S. Srivastava, H. Kino and C. Joachim, Nanoscale, in press (2016)
- Parallel quantum circuit in a tunnel junction. O. Faizy, G. Dridi, C. Joachim, Sci. Rep. (2016) submitted.
 

[1] Refers to sections of the QIPC roadmap (version 1.8) which can be found at: http://qurope.eu/content/qipc-roadmap

 

 

Leader: 
Christian Joachim

Quantum Information and Technologies (QITE)

Research Type: 
Theory
Experiment

Increasingly smaller and faster, devices for information processing are everywhere. Nevertheless, the impressive development of such technologies is threatened if the possibilities offered by quantum physics are not considered.

Leader: 
Luca Guidoni and Pérola Milman

molecular quantum spintronics

Research Type: 
Experiment

 

we aim at developing devices and protocols to read out and process quantum information using individual molecular spins embedded in electronic circuits. To this end, prototypical hybrid nano-devices addressing single molecular spins will be designed and reliable methods for their realization will be developed. Core of such nano-architectures are magnetic molecules, specifically functionalized to graft electrodes, and exploited as spin (qu)bits.

Leader: 
Affronte

Physics of Quantum Information

Research Type: 
Experiment

Theory of quantum information

Quantum Transport in Nanoelectronic Devices

Stochastic Effects in Artificial Intelligence

Metamaterials and Atom Based Photonics

Foundations of Physics of Time

Leader: 
Enrico Prati

Understanding Google announcement about the D-Wave machine

Summary: 

A note by the QUROPE Virtual Institutes and Facilities on recent developments in quantum annealing.

The QUROPE Virtual Institutes and Facilities have produced a document aimed at understanding what is the take away message of the last preprint of Google researchers about the D-Wave machine (see this news).

The document can be downloaded following this link

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