95 research outputs found
Microscopic dynamics and effective Landau-Zener transition in quasi-adiabatic preparation of spatially-ordered states of Rydberg excitations
We examine the adiabatic preparation of spatially-ordered Rydberg excitations
of atoms in finite one-dimensional lattices by frequency-chirped laser pulses,
as realized in a number of recent experiments simulating quantum Ising model.
Our aims are to unravel the microscopic mechanism of the phase transition from
the unexcited state of atoms to the antiferromagnetic-like state of Rydberg
excitations by traversing an extended gapless phase, and to estimate the
preparation fidelity of the target state in a moderately sized system amenable
to detailed numerical analysis. We find that, in the basis of the bare atomic
states, the system climbs the ladder of Rydberg excitations predominantly along
the strongest-amplitude paths towards the final ordered state. We show that,
despite its complexity, the interacting many-body system can be described as an
effective two-level system involving a pair of lowest-energy instantaneous
collective eigenstates of the time-dependent Hamiltonian. The final preparation
fidelity of the target state can then be well approximated by the Landau-Zener
formula, while the nonadiabatic population leakage during the passage can be
estimated using a perturbative approach applied to the instantaneous collective
eigenstates.Comment: revised m
Ultralong temporal coherence in optically trapped exciton-polariton condensates
Funding: This work was supported by Grant No. EPSRC EP/S014403/1. K.O. acknowledges EPSRC for PhD studentship support through grant no. EP/L015110/1. P.S. acknowledges support by Westlake University (Project No. 041020100118), Program 2018R01002 supported by Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang, and bilateral Greece-Russia Polisimulator project co-financed by Greece and the EU Regional Development Fund.We investigate an optically trapped exciton-polariton condensate and observe temporal coherence beyond 1 ns in duration. Due to the reduction of the spatial overlap with the thermal reservoir of excitons, the coherence time of the trapped condensate is more than an order of magnitude longer than that of an untrapped condensate. This ultralong coherence enables high-precision spectroscopy of the trapped condensate, and we observe periodic beats of the field correlation function due to a fine energy splitting of two polarization modes of the condensate. Our results are important for realizing polariton simulators with spinor condensates in lattice potentials.PostprintPeer reviewe
Occurrence of viruses and Xiphinema spp. in vineyards of the greek islands of Paros and Lemnos
A survey was carried out during 1997–2000 in order to determine the incidence of grapevine viruses and
their associated nematode-vectors in Paros and Lemnos, the two main islands of the Aegean sea producing V.Q.P.R.D.
wines. Nine viruses, Grapevine fanleaf nepovirus (GFLV), Grapevine leafroll associated closterovirus (GLRaV) 1, 2, 3,
6 and 7, Grapevine vitivirus (GV) A and B, Grapevine fleck virus (GFkV) and three species of Xiphinema, X. index, X.
italiae and X. pachtaicum, were recorded. While the three nematode species occurred in both islands, the virological
problems of each island were different. In Paros, GFLV and its vector X. index were widespread in selfrooted vineyards,
while GVA also occurred in asymptomatic vines. In Lemnos, where vineyards use American rootstocks, the
Closteroviruses and GVA were the major problem, explaining the high incidence of leafroll and stem grooving
Qubit Analog with Polariton Superfluid in an Annular Trap
We report on the experimental realization and characterization of a qubit
analog with semiconductor exciton-polaritons. In our system, a condensate of
exciton-polaritons is confined by a spatially-patterned pump laser in an
annular trap that supports energy-degenerate circulating currents of the
polariton superfluid. Using temporal interference measurements, we observe
coherent oscillations between a pair of counter-circulating superfluid vortex
states of the polaritons coupled by elastic scattering off the laser-imprinted
potential. The qubit basis states correspond to the symmetric and antisymmetric
superpositions of the two vortex states forming orthogonal double-lobe spatial
wavefunctions. By engineering the potential, we tune the coupling and coherent
oscillations between the two circulating current states, control the energies
of the qubit basis states, and initialize the qubit in the desired state. The
dynamics of the system is accurately reproduced by our theoretical two-state
model, and we discuss potential avenues to achieve complete control over our
polaritonic qubits and realize controllable interactions between such qubits to
implement quantum gates and algorithms analogous to quantum computation with
standard qubits
Description of the first-stage juveniles of Xiphinema cretense and X. herakliense - Distribution of Xiphinema and Longidorus species in olive orchards and grapevines in Crete, Greece
The occurrence of nematodes of the family Longidoridae was investigated in soil samples collected from cultivated and wild olives and grapevines in Crete. The first-stage juveniles of Xiphinema cretense and X. herakliense are described for the first time. The species X. israeliae, X. cretense, X. herakliense and Longidorus pseudoelongatus, previously recorded exclusively from olives in Crete, are herein reported in the rhizosphere of grapevines. Also L. iranicus is reported for the first time in cultivated olive, while X. italiae and L. closelongatus are reported for the first time in wild olive in Crete. Data on the occurrence of phytoparasitic nematode species in cultivated olives, wild olives and grapevines are updated with those previously published.This research was supported by grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the
Mediterranean basin’ from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, “Una manera de hacer Europa”. I.G. Birmpilis and E. Nasiou were employed by the ARIMNET-PESTOL-IVE project.Peer reviewe
Compatibility of fluazaindolizine and oxamyl with Pasteuria penetrans on spore attachment to juveniles of Meloidogyne javanica and M. incognita
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