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Research Center for Quantum Information
Institute of Physics, Slovak Academy of Sciences
Dúbravská cesta 9, 84511 Bratislava, Slovakia
Tel: (+421 +2) 20910701
Fax: (+421 +2) 54776085

N E W S  old news 
8.6.2018 Publication
Shorter unentangled proofs for ground state connectivity
Can one considerably shorten a proof for a quantum problem by using a protocol with a constant number of unentangled provers? We consider a frustrationfree variant of the QCMA complete ground state connectivity (GSCON) problem for a system of size n with a proof of superlinear size. We show that we can shorten this proof in QMA(2): There exists a twocopy, unentangled proof with length of order n, up to logarithmic factors, while the completeness–soundness gap of the new protocol becomes a small inverse polynomial in n.
by
Libor Caha, Daniel Nagaj, Martin Schwarz
Quantum Inf. Processing 17, 174 (2018)
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QETWORK APVV140878, SASPRO

5.6.2018 Publication
Clocks in Feynman's computer and Kitaev's local Hamiltonian: Bias, gaps, idling, and pulse tuning
We present a collection of results about the clock in Feynman's computer construction and Kitaev's local Hamiltonian problem. First, by analyzing the spectra of quantum walks on a line with varying endpoint terms, we find a better lower bound on the gap of the Feynman Hamiltonian, which translates into a less strict promise gap requirement for the quantumMerlinArthur–complete local Hamiltonian problem. We also translate this result into the language of adiabatic quantum computation. Second, introducing an idling clock construction with a large state space but fast Cesaro mixing, we provide a way for achieving an arbitrarily high success probability of computation with Feynman's computer with only a logarithmic increase in the number of clock qubits. Finally, we tune and thus improve the costs (locality and gap scaling) of implementing a (pulse) clock with a single excitation.
by
Libor Caha, Zeph Landau, and Daniel Nagaj
Phys. Rev. A 97, 062306 (2018)
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QETWORK APVV140878, OAQS VEGA 2/0130/15, SASPRO

16.5.2018 Award
Gold Medal of Slovak Academy of Sciences for Prof. Vladimír Bužek
For his extraordinary achievements in physics and also to celebrate his anniversary Prof. Vladimír Bužek was awarded the highest prize of Slovaka Academy of Sciences  SAS Gold Medal (in Slovak "Zlatá medaila SAV"). Prof. Bužek founded in Slovakia the school of quantum optics and quantum information processing. He is recognised worldwide for his discoveries on quantum cloning machines, quantum protocols for secret sharing and anonymous voting, quantum estimations, quantum programmable processors, etc.  +++  (in Slovak)

15.5.2018 Award
Who is The Young Scientist of the Year 2017 in Slovakia?
We are all happy that our colleague Daniel Reitzner was awarded a prestigous national prize "Mladý vedec roka 2017" (Young Scientist of the Year 2017) for his work on quantum walks and quantum incompatibility. Congratulations!
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1.3.2018 Workshop
CEQIP 2018
We organize already 15th edition of traditional CEQIP workshops
in June 1316 in Smolenice castle. Come to enjoy the unique atmosphere
of these meetings. We are looking forward to meet you there.
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S E M I N A R S
 more 
07/06 11:00
Tom Bullock (Turku)
NonMarkovian entanglement breaking channels

V I S I T O R S
 history 
02.0530.11 Seyed Arash Ghoreishi
(Ferdowsi university of Mashhad, Mashhad, Iran)
03.0617.06 Tom Bullock
(Turku University, Turku, Finland)
30.0703.08 Leonardo Novo
(Université Libre de Bruxelles, Belgium)
30.0703.08 Shantanav Chakraborty
(Université Libre de Bruxelles, Belgium)


