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	Author	McNaughton, B.; Milošević, M.V.; Perali, A.; Pilati, S.
	Title	Boosting Monte Carlo simulations of spin glasses using autoregressive neural networks			Type	A1 Journal article
	Year	2020	Publication	Physical Review E	Abbreviated Journal	Phys Rev E
	Volume	101	Issue	5	Pages	053312
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The autoregressive neural networks are emerging as a powerful computational tool to solve relevant problems in classical and quantum mechanics. One of their appealing functionalities is that, after they have learned a probability distribution from a dataset, they allow exact and efficient sampling of typical system configurations. Here we employ a neural autoregressive distribution estimator (NADE) to boost Markov chain Monte Carlo (MCMC) simulations of a paradigmatic classical model of spin-glass theory, namely, the two-dimensional Edwards-Anderson Hamiltonian. We show that a NADE can be trained to accurately mimic the Boltzmann distribution using unsupervised learning from system configurations generated using standard MCMC algorithms. The trained NADE is then employed as smart proposal distribution for the Metropolis-Hastings algorithm. This allows us to perform efficient MCMC simulations, which provide unbiased results even if the expectation value corresponding to the probability distribution learned by the NADE is not exact. Notably, we implement a sequential tempering procedure, whereby a NADE trained at a higher temperature is iteratively employed as proposal distribution in a MCMC simulation run at a slightly lower temperature. This allows one to efficiently simulate the spin-glass model even in the low-temperature regime, avoiding the divergent correlation times that plague MCMC simulations driven by local-update algorithms. Furthermore, we show that the NADE-driven simulations quickly sample ground-state configurations, paving the way to their future utilization to tackle binary optimization problems.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000535862000014	Publication Date	2020-05-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1539-3755; 1550-2376	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.366	Times cited	15	Open Access
	Notes	; The authors thank I. Murray, G. Carleo, and F. RicciTersenghi for useful discussions. Financial support from the FAR2018 project titled “Supervised machine learning for quantum matter and computational docking” of the University of Camerino and from the Italian MIUR under Project No. PRIN2017 CEnTraL 20172H2SC4 is gratefully acknowledged. S.P. also acknowledges the CINECA award under the ISCRA initiative, for the availability of high performance computing resources and support. M.V.M. gratefully acknowledges the Visiting Professorship program at the University of Camerino that facilitated the collaboration in this work. ;			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:170244			Serial	6463
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	Author	Jalali, H.; Ghorbanfekr, H.; Hamid, I.; Neek-Amal, M.; Rashidi, R.; Peeters, F.M.
	Title	Out-of-plane permittivity of confined water			Type	A1 Journal article
	Year	2020	Publication	Physical Review E	Abbreviated Journal	Phys Rev E
	Volume	102	Issue	2	Pages	022803
	Keywords	A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	The dielectric properties of confined water is of fundamental interest and is still controversial. For water confined in channels with height smaller than h = 8 angstrom, we found a commensurability effect and an extraordinary decrease in the out-of-plane dielectric constant down to the limit of the dielectric constant of optical water. Spatial resolved polarization density data obtained from molecular dynamics simulations are found to be antisymmetric across the channel and are used as input in a mean-field model for the dielectric constant as a function of the height of the channel for h > 15 angstrom. Our results are in excellent agreement with a recent experiment [L. Fumagalli et al., Science 360, 1339 (2018)].
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000560660400004	Publication Date	2020-08-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1539-3755; 1550-2376	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.366	Times cited	38	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. ;			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:171157			Serial	6574
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	Author	Wang, Q.; Lin, S.; Liu, X.; Xu, W.; Xiao, Y.; Liang, C.; Ding, L.; Peeters, F.M.
	Title	Photoluminescence and electronic transition behaviors of single-stranded DNA			Type	A1 Journal article
	Year	2021	Publication	Physical Review E	Abbreviated Journal	Phys Rev E
	Volume	104	Issue	3	Pages	034412
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Due to the potential application of DNA for biophysics and optoelectronics, the electronic energy states and transitions of this genetic material have attracted a great deal of attention recently. However, the fluorescence and corresponding physical process of DNA under optical excitation with photon energies below ultraviolet are still not fully clear. In this work, we experimentally investigate the photoluminescence (PL) properties of single-stranded DNA (ssDNA) samples under near-ultraviolet (NUV) and visible excitations (270 similar to 440 nm). Based on the dependence of the PL peak wavelength (lem) upon the excitation wavelength (lex), the PL behaviors of ssDNA can be approximately classified into two categories. In the relatively short excitation wavelength regime, lem is nearly constant due to exciton-like transitions associated with delocalized excitonic states and excimer states. In the relatively long excitation wavelength range, a linear relation of lem = Alex + B with A 0 or A < 0 can be observed, which comes from electronic transitions related to coupled vibrational-electronic levels. Moreover, the transition channels in different excitation wavelength regimes and the effects of strand length and base type can be analyzed on the basis of these results. These important findings not only can give a general description of the electronic energy states and transitional behaviors of ssDNA samples under NUV and visible excitations, but also can be the basis for the application of DNA in nanoelectronics and optoelectronics.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000703562300002	Publication Date	2021-09-20
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2470-0053	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	2.366	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.366
	Call Number	UA @ admin @ c:irua:182517			Serial	7009
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