Fotis K. Diakonos
National and Kapodistrian University of Athens
Particle physicsQuantum chromodynamicsPhysicsStatistical physicsCritical point (thermodynamics)Phase transitionPhase spaceCritical exponentNuclear physicsCritical phenomenaHadronPionFermi accelerationIntermittencyQuantum electrodynamicsMathematicsQuantum mechanicsClassical mechanicsLarge Hadron ColliderHomogeneous space
254Publications
26H-index
2,763Citations
Publications 179
Newest
#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 19
#2Stelios M. Potirakis (UWest: University of the West)H-Index: 17
Last. Efstratios K. Kosmidis (A.U.Th.: Aristotle University of Thessaloniki)H-Index: 15
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Abstract Combining concepts of artificial neural networks (ANNs) with the stochastic dynamics of Ising spin lattices we introduce a hybrid model, the hybrid spin model (HSM). We find that the HSM carries the critical/tricritical fluctuations of the 2D Ising model and allows for an accurate estimation of the isothermal critical/tricritical exponents of 2D Ising universality class. Our work clearly demonstrates that HSM launches a new category of models supporting alternative pathways for the real...
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#2Ioannis BrouzosH-Index: 12
Last. G. TheocharisH-Index: 1
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We propose a fast and robust quantum state transfer protocol employing a Su-Schrieffer-Heeger chain, where the interchain couplings vary in time. Based on simple considerations around the terms involved in the definition of the adiabatic invariant, we construct an exponential time-driving function that successfully takes advantage of resonant effects to speed up the transfer process. Using optimal control theory, we confirm that the proposed time-driving function is close to optimal. To unravel ...
2 CitationsSource
#1M. RöntgenH-Index: 5
#2Maxim PyzhH-Index: 4
Last. Peter SchmelcherH-Index: 56
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Degeneracies in the energy spectra of physical systems are commonly considered to be either of accidental character or induced by symmetries of the Hamiltonian. We develop an approach to explain degeneracies by tracing them back to symmetries of an effective Hamiltonian derived by subsystem partitioning. We provide an intuitive interpretation of such latent symmetries by relating them to corresponding local symmetries in the powers of the underlying Hamiltonian matrix. As an application, we rela...
2 CitationsSource
#1Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
Last. Stelios M. PotirakisH-Index: 17
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We show that the spontaneous symmetry breaking can be defined also for finite systems based on the properly defined jump probability between the ground states in the 2d and 3d Ising models on a square and a cubic lattice respectively. Our analysis reveals the existence of an interval in the temperature (control parameter) space within which the spontaneous symmetry breaking takes place. The upper limit of this region is the pseudocritical point where the symmetric vacuum bifurcates in energetica...
We explore wave-mechanical scattering in two spatial dimensions assuming that the corresponding potential is invariant under linear symmetry transforms such as rotations, reflections and coordinate exchange. Usually the asymptotic scattering conditions do not respect the symmetries of the potential and there is no systematic way to predetermine their imprint on the scattered wave field. Here we show that symmetry induced, non-local, divergence-free currents can be a useful tool for the descripti...
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Last. Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
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The concept of the generalized continuity equation (GCE) was recently introduced in [J. Phys. A: Math. and Theor. {\bf 52}, 1552034 (2019)], and was derived in the context of Nindependent Schr\"{o}dinger systems. The GCE is induced by a symmetry transformation which mixes the states of these systems, even though the Nsystem Lagrangian does not. As the Nsystem Schr\"{o}dinger Lagrangian is not invariant under such a transformation, the GCE will involve source terms which, under certain c...
#2Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
Last. Alexandros GezerlisH-Index: 18
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The properties of neutron matter are integral to the correct description of neutron stars as well as the description of neutron-rich nuclei. One key property of neutron matter is its superfluid behaviour in a range of densities relevant to the inner crust of neutron stars. This work investigates the finite-size effects in the pairing gap of a pure neutron matter superfluid system at densities found in the inner crust of cold neutron stars. The BCS (Bardeen-Cooper-Schrieffer) treatment of superfl...
2 CitationsSource
#1I. BrouzosH-Index: 1
#1Ioannis Brouzos (CNRS: Centre national de la recherche scientifique)H-Index: 12
Last. Georgios Theocharis (CNRS: Centre national de la recherche scientifique)H-Index: 29
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We show that it is possible to successfully, rapidly, and robustly transfer a topological vibrational edge mode across a time-varying mechanical chain. The stiffness values of the springs of the chain are arranged in an alternating staggered way such that we obtain a mechanical analog of the quantum Su-Schrieffer-Heeger model, which exhibits a nontrivial topological phase. Using optimal control methods, we are able to design control schemes for driving the stiffness parameters such that the tran...
1 CitationsSource
#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 19
#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 4
Last. Fotios K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 13
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The detection of power-laws in real data is a demanding task for several reasons. The two, more frequently met, being: (i) real data possess noise which affects significantly the power-law tails and (ii) there is no solid tool for the discrimination between a power-law, valid in a specific range of scales, from other functional forms like log-normal or stretched exponential distributions. In the present report we demonstrate, employing simulated and real data, that using wavelets it is possible ...
1 CitationsSource
#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 19
#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 4
Last. Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
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Abstract We show that, in continuous phase transitions, the order parameter fluctuations in time, are characterized by a resonant phenomenon, occurring whenever a physical system enters in a critical region. It is realized in the mean waiting time 〈 λ 〉 of the order parameter time-series, in the immediate neighbourhood of its equilibrium (mean) value. By varying the control parameter within the critical region, 〈 λ 〉 becomes maximum at the critical point. To illustrate this resonant behaviour, w...
1 CitationsSource