Time as an illusion created by entanglement in Physical Review A featured in WIRED

ISC researchers Alessandro Coppo and Paola Verrucchi, in collaboration with Prof. A. Cuccoli from the University of Florence, have published an intriguing study in Physical Review A. The work has garnered attention from prominent publications such as New Scientist and Wired.

They consider  a simple and physically relevant example  where the time evolution of a system can  be determined by the entanglement with its clock.… Read the rest

Optimal Quantum Key Distribution Networks in npj Quantum information

ISC researchers C. Castellano, V.Brosco and L. Pilozzi coauthored an interesting work published in npj quantum information.

Optimal quantum key distribution networks: capacitance versus security

L. Cirigliano, V.Brosco, C. Castellano, C. Conti, L. Pilozzi,  npj Quantum Information 10, 44 (2024)

Abstract

The rate and security of quantum communications between users placed at arbitrary points of a quantum communication network depend on the structure of the network, on its extension and on the nature of the communication channels.

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Long-Lived Higgs Modes in Strongly Correlated Condensates in Physical Review Letters

ISC-Director José Lorenzana  has recently collaborated on a compelling research work that appeared  in Physical Review Letters. J. Lorenzana and G. Seibold, Long-Lived Higgs Modes in Strongly Correlated Condensates, Phys. Rev. Lett. 132, 026501 (2024).

Condensed matter physics and high-energy physics has cross fertilizing each other for decades. One paradigmatic example is superconductivity, where Anderson’s mechanism giving mass to the Goldstone mode in a superconductor was taken by Higgs to explain mass generation in the

Standard model of elementary particles.… Read the rest

Superconducting Qubit Based on Twisted Cuprate Van der Waals Heterostructures in Physical Review Letters

ISC researcher Valentina Brosco coauthored an interesting research proposing a novel superconduting qubit desigm. The work has been selected for an Editor’s Suggestion in Physical Review Letters, see Superconducting Qubit Based on Twisted Cuprate Van der Waals Heterostructures V. Brosco, G. Serpico, V. Vinokur, N. Poccia and U. Vool, Phys. Rev. Lett. 132, 017003 (2024).

Abstract

Van-der-Waals assembly enables the fabrication of novel Josephson junctions featuring an atomically sharp interface between two exfoliated and relatively twisted Bi2Sr2CaCu2O8+x (Bi2212) flakes.

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Enhanced Critical Field at an Oxide Interface in Nano Letters

Almost uncharged and non-magnetic electrons explain resilience to magnetic fields in exotic superconductors

ISC Director, J. Lorenzana, coauthored an interesting work on Nano Letters, Enhanced Critical Field of Superconductivity  at an Oxide Interface, Athby H. Al-Tawhid
A. H. Al-Tawhid, S. J. Poage, S. Salmani-Rezaie, A. Gonzalez, S. Chikara, D. A. Muller, D. P. Kumah, Maria N. Gastiasoro, J. Lorenzana, and K.… Read the rest

2D High-Temperature Superconductor Integration in Contact Printed Circuit Boards in ACS Applied Materials and Interfaces

ISC researcher Valentina Brosco coauthored an interesting research article published in ACS Applied Materials and Interfaces, C. Saggau et al.2D High-Temperature integration in Contact Printed Circuit Boards, ACS Appl. Mater. Interfaces 44, 51558 (2023).  The work paves the way to the realization of novel  printed circuits and devices integrating atomically thin high-Tc superconducting  films.

2D High-Temperature Superconductor Integration in Contact Printed Circuit Boards

Inherent properties of superconducting Bi2Sr2CaCu2O8+x films, such as the high superconducting transition temperature Tc, efficient Josephson coupling between neighboring CuO layers, and fast quasiparticle relaxation dynamics, make them a promising platform for advances in quantum computing and communication technologies.

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Waveguide QED with Quadratic Light-Matter Interactions – PRX Quantum

ISC researcher S. Felicetti is the lead author of a research article now published in PRX Quantum, in collaboration with Aalto University (Helsinki) and the Institute of Fundamental Physics IFF-CSIC (Madrid): U. Alushi, T. Ramos, J.-J. G.-Ripoll, R. Di Candia, and S. Felicetti PRX Quantum 4, 030326 (2023).

Quadratic light-matter interactions are nonlinear couplings such that quantum emitters interact with photonic or phononic modes exclusively via the exchange of excitation pairs.… Read the rest

Mechanism for fluctuating pair density wave in Nature Communications

ISC researcher L. Fanfarillo coauthored an interesting article now published in Nature Communications, C. Setty, L. Fanfarillo and P. J. Hirschfeld Nat. Comm.  3181 (2023).

In weakly coupled BCS superconductors, only electrons within a tiny energy window around the Fermi energy, EF, form Cooper pairs. This may not be the case in strong coupling superconductors such as cuprates, FeSe, SrTiO3 or cold atom condensates where the pairing scale, EB, becomes comparable or even larger than EF.

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Heat flow on the nanoscale in La Rivista del Nuovo Cimento (2023)

ISC researcher Stefano Lepri and ISC associate Roberto Livi coauthored an interesting review article  showing how heat flow is different on the nanoscale.

G. Benenti, D. Donadio, S. Lepri and R. Livi, Non Fourier heat transport in nanosystems, La Rivista del Nuovo Cimento (2023)

Energy transfer in small nano-sized systems can be very different from that in their macroscopic counterparts due to reduced dimensionality, interaction with surfaces, disorder, and large fluctuations.

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The Hyperspin Machine in Nature Communications

Our colleagues Claudio Conti and Marcello Calvanese-Strinati have recently published a beautiful theoretical work showing how coupled parametric oscillators can simulate multidimensional continuous spin models. Read more on Nature Communications, 13 7248 (2022)

Abstract

From condensed matter to quantum chromodynamics, multidimensional spins are a fundamental paradigm, with a pivotal role in combinatorial optimization and machine learning. Machines formed by coupled parametric oscillators can simulate spin models, but only for Ising or low-dimensional spins.

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SIF Prize “Sergio Panizza e Gabriele Galimberti” to D. Pierangeli

The prize Sergio Panizza e Gabriele Galimberti from the Italian Physical Society (SIF) was awarded to  Dr.Davide Pierangeli, researcher in our Institute, “for his groudbreaking experimental work in the field of  non-linear photonics. Among D. Pierangeli’s works, of particular relevance is the first observation of the breaking of replica symmetry in disordered photorefractive media.”

The original work D. Pierangeli, A. Tavani, F.… Read the rest

Thouless pumping of light with a twist – Nature Physics News and Views

ISC researchers L. Pilozzi and V. Brosco write on a recent experiment [1] with photonic waveguides  which demonstrates the connection between non-Abelian holonomies and adiabatic particle transport, paving the way to the geometric and topological control of light trajectories.

The experiment by Sun and colleagues represents one of the few observations so far of the non-Abelian Wilczek–Zee holonomy. But by employing Thouless pumping as a tool for probing non-Abelian topological physics, it also paves the way for the geometric control of photon states and light trajectories in real space — a fundamental step in the direction of photonic information processing [2].… Read the rest

News and Views on “Thermally reconfigurable random lasers”

Light can control microparticles and microstructures can shape light, leading to a wide range of practical applications as well as interesting physics.

By combining optically controlled micro-heaters with thermophilic particles attracted by them researchers form University College London obtained microlasers with programmable and reversible patterns. This achievement is a nice demonstration of what happens when colloidal science meets photonics and is now published in Nature Physics and highlighted by Neda Ghofraniha in News and Views .… Read the rest

Photonics and the Nobel Prize in Physics – News and Views on Nature Photonics

ISC director, Prof. Claudio Conti and Prof. Eugenio Del Re  share their thoughts on  the role of  photonics experiments in the development of complex systems and spin glass theory. Read the full story  on Nature Photonics News and Views.

Photonics and the Nobel Prize in Physics
Giorgio Parisi recently shared a Nobel Prize in Physics for his contribution to the theory of complex systems.

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Nature Communications : Hyperbolic optics and superlensing from self-induced topological transitions

Claudio Conti and Eugenio Del Re co-authored an interesting work published on Nature Communications  demonstrating experimentally self-induced topological transitions from elliptical to hyperbolic k-space manifolds in room-temperature photorefractive KTN.

Hyperbolic optics and superlensing in room-temperature KTN from self-induced k-space topological transitions

Y.Gelkop, F.Di Mei, S. Frishman, Y. Garcia, L. Falsi, G. Perepelitsa, C. Conti, E. Del Re , and A. J.

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QUANCOM project launched!

ISC researchers, C. Conti, L. Pilozzi and V. Brosco, participate in the new PON project QUANCOM.

Security technologies in both the network transmission layers and in the application layers are becoming more and more complex and sophisticated but, nevertheless these efforts, they are not completely immune to attacks. In fact, even the computing power (parallel and distributed thanks to the network resource) is increasing and available to organizations that, for various purposes, have interests in appropriating of sensitive data.

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Time and classical equations of motion from quantum entanglement

ISC Researcher Paola Verrucchi and Collaborators wrote a beatiful and elegant work investigating the concept of time in quantum mechanics, now published in  Nature Communications, see C. Foti, A.Coppo, G. Barni, A. Cuccoli and P. Verrucchi, Time and classical equations of motion from quantum entanglement via the Page and Wootters mechanism with generalized coherent states, Nature Communications 12,  1787 (2021).

The figure shows the interaction between a classical clock and a quantum system.… Read the rest

Photonics Research Special Issue now available online

ISC researcher Laura Pilozzi, co-edited the Photonics Research Special Issue Topological Photonics and beyond: novel concepts and recent avances, now available online

 

 

Topological photonics has been opening exciting opportunities in recent optics research. This Special Issue provides a snapshot and overview of the recent advances in this thriving field of research. It features six papers and one review article, by some of the leading experts in the field, covering various aspects of topological photonics research.… Read the rest

Replica Symmetry Breaking Maps in Random Laser, ACS Photonics (2021)

ISC Researchers build for the first time replica symmetry breaking  maps to visualize Random Laser activity on ACS Photonics 2021

In the past decade, complex networks of light emitters are proposed as novel platforms for photonic circuits and lab-on-chip active devices. Lasing networks made by connected multiple gain components and graphs of nanoscale random lasers (RLs) obtained from complex meshes of polymeric nanofibers are successful prototypes.… Read the rest

Dielectric permittivity of aqueous solutions of electrolytes probed by THz time-domain and FTIR spectroscopy – Phys. Lett. A.

A. De Ninno, E. Nikollari, M. Missori and F. Frezza have published Dielectric permittivity of aqueous solutions of electrolytes probed by THz time-domain and FTIR spectroscopy in Physics Letters A.
Highlights
• The permittivity of water is described in terms of two independent Debye functions.
• The model is also applied to chloride solutions.
• The excess high frequency response is explained without ad hoc corrective terms.… Read the rest

Neuromorphic Computing Waves – PRL

Giulia Marcucci, Davide Pierangeli, and Claudio Conti have published Theory of Neuromorphic Computing by Waves: Machine Learning by Rogue Waves, Dispersive Shocks, and Solitons in Physical Review Letters.

Artificial neural networks with nonlinear waves as a computing reservoir are the subject of the paper in which the universality and the conditions to learn a dataset in terms of output channels and nonlinearity are discussed.… Read the rest

Quantum Measurement Cooling selected for highlights of PRL

Congratulations go to Paola Verrucchi and the co-authors of Quantum Measurement Cooling, recently published in Physical Review Letters, for having been selected as editor’s suggestion and featured article.

Physics.aps.org dedicates synopsis for the article as well.… Read the rest

Optical networks as complex lasers

A review article in the physics-central, physics-buzz blog has appeared presenting the recent results of G. Giacomelli, S. Lepri (ISC) and C.Trono (IFAC) about the LANER (lasing network):

http://physicsbuzz.physicscentral.com/2019/02/meet-laner-network-laser.html
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.99.023841Read the rest

Mauro Missori awarded a CNR/CACH Bilateral Agreement

Mauro Missori awarded a CNR Bilateral Agreement with the Chinese Academy of Cultural Heritage (CACH) with the project “Nanoscale degradation indexes of ancient Chinese and Italian papers for conservation & restoration applications”.

The aim of this joint research project is to develop degradation indexes of ancient Chinese and Italian papers for restoration applications. These activities require the use of specific physical and chemical diagnostics technique at the nanoscale suitable for the cellulose-based materials and, in general, for natural polymeric fibers.… Read the rest

Flexible and Wearable Metamaterials: new frontiers in biomedical and safety&security applications

Metamaterials are engineered material having periodic structures that exhibit unique properties when they interact with electromagnetic waves in comparison with natural materials. They offer interesting applications throughout the electromagnetic spectrum and are crucial in the Terahertz (THz) frequency band which lies between microwave and infrared and thus invisible to the human eye. This band is a new frontier both for research and technological applications in sectors ranging from astronomy to cultural heritage.… Read the rest

Topological Laser

The cascade of resonant PT-symmetric topological structures is shown to emit laser light with a frequency comb spectrum. We consider optically active topological lattices supporting edge modes at regularly spaced frequencies. When the amplified resonances in the PT-broken regime match the edge modes of the topological gratings, we predict the emission of discrete laser lines. A proper design enables the engineering of the spectral features for specific applications.… Read the rest

Observation of replica symmetry breaking in disordered nonlinear wave propagation

Davide Pierangeli, Andrea Tavani, Fabrizio Di Mei, Aharon J. Agranat, Claudio Conti & Eugenio DelRe have published an article Observation of replica symmetry breaking in disordered nonlinear wave propagation in nature communications.
Abstract
A landmark of statistical mechanics, spin-glass theory describes critical phenomena in disordered systems that range from condensed matter to biophysics and social dynamics. The most fascinating concept is the breaking of replica symmetry: identical copies of the randomly interacting system that manifest completely different dynamics.… Read the rest

The LANER: optical networks as complex lasers

Complex Active Optical Networks as a New Laser Concept by Stefano Lepri, Cosimo Trono and Giovanni Giacomelli has been published in Physical Review Letters.

The introduction of one or more active sections in a complex network may lead to laser emission. We call this system LANER (lasing network). As in the usual laser, when the gains are sufficiently high coherent emission is produced; in this case, the full network becomes a complicated, multipath and multigain cavity for the optical field.… Read the rest

How to build a quantum Newton’s cradle

A quantum analogue of the popular “Newton’s cradle” toy has been proposed by a duo of physicists in Italy. Like momentum transferred in the toy, the team argues that it should be possible to achieve the nearly perfect transmission of a quantum wavefunction along a line of ultracold atoms in a 1D Bose–Einstein condensate. According to the pair, the work could help develop quantum-information systems that achieve high-quality wave transmission […]

read articleRead the rest

Newton cradle

Newton’s cradle (Fig. 1) is a valuable paradigm of how physical mechanisms are concealed into nature. It is a device based on classical mechanics that demonstrates the conservation of momentum and energy. On the other hand, Quantum Mechanics has been shown to be one of most prolific sources of unexpected and hard-to-understand phenomena. Therefore, achieving a machine which is a paradigm for the quantum nature of a system is an engrossing challenge.… Read the rest

Anomalous Heat Transport in Low Dimensions

Many phenomena in nature occur under nonequilibrium stationary conditions. For instance, an electric current is obtained by applying an electric field along a conductor or heat is transported when a temperature gradient is established between two boundaries of a material. Despite their ubiquiteness and importance in everyday life many aspects of such phenomena are still under debate in the theoretical physics community.

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Asymmetric Wave Transport in Nonlinear System

Deterministic chaos, fractal structures and other beautiful phenomena are manifestations of the nonlinear character of forces which govern our world. Besides a revolutionary change in our approach to predictability, these discoveries had great impact on technological applications.  Among the most fascinating ones is  the possibility to control energy flows by tuning nonlinear features of complex materials.

In the context of wave propagation trough nonlinear media, the simplest form of control would be to devise a “wave diode”  in which electromagnetic or elastic waves are transmitted differently along two opposite propagation directions.… Read the rest

Review on Spatio-temporal phenomena in complex systems with time delays

Serhiy Yanchuk and Giovanni Giacomelli published a topical review in Journal of Physics A: Mathematical and Theoretical.

Real-world systems can be strongly influenced by time delays occurring in self-coupling interactions, due to unavoidable finite signal propagation velocities. When the delays become significantly long, complicated high-dimensional phenomena appear and a simple extension of the methods employed in low-dimensional dynamical systems is not feasible.… Read the rest

Biomimetic antimicrobial cloak by graphene-oxide agar hydrogel

Massimiliano Papi and others published a scientific report on an antibacterial cloak produced by laser printing graphene oxide hydrogels mimicking the Cancer Pagurus carapace.… Read the rest

Ionic liquids: a spectroscopic investigation

Ionic liquids (IL) are salts formed by organic cations, like imidazolium, pyrrolidinium, ammonium or alkyl phosphonium, and organic/inorganic anions, like hexafluorophosphate, tetrafluoroborate, triflate, dicyanamide, tetracyanamethanide or bis(trifluoromethanesulfonyl)imide (TFSI). The presence of such bulky and asymmetric ions decreases the ion-ion interactions and lowers the melting point with respect to more classical salts, reaching values as low as -20°C.

ILs posses many peculiar properties, such as an extremely low vapor pressure, a high ionic conductivity, a high thermal, chemical and electrochemical stability, a high thermal capacity and a good solvent capability.… Read the rest

Solid state hydrogen storage

Hydrogen is attracting renewed interest as an energy carrier, due to the necessity of finding ecological energy media which may decrease the environmental pollution from fossil fuels. Hydrogen storage represents a nodal point for the development of a hydrogen economy.

Of the three possible ways to store hydrogen, i.e. as high pressure gas, as a liquid (~20 K at atmospheric pressure), or as hydrides in solids, the latter one appears as the most promising, due to the high mass and volume density and safety.… Read the rest

Volume collapse transition in Ce

Crystalline Ce has a remarkable phase diagram in that is the solid state analogue of a Van der Walls system with a line of discontinuous transitions ending at a critical point.

The two phases alpha and gamma have the same cubic symmetry and differ only on density just like water and vapor but in the solid state!.

However unlike water and vapor the critical exponents close to the critical point are not three dimensional Ising critical exponents, as one would naively guess from symmetries, but  classical (Gaussian) exponents.… Read the rest

Polarons in strongly correlated systems

In system with strong electron-phonon interaction, the carriers loose mobility, ultimately acquiring polaronic character. A polaron is a state in which the phonon and electron degrees of freedom are strongly entangled, and the presence of an electron is associated to a finite lattice distortion, which in turn bind

Phonon distribution function P(n) and magnetic polaron size Lp as function of the exchange coupling J, signalizing the formation of the spin/lattice polaron

s the electron leading to the so-called self-trapping effect.… Read the rest

Graphene and carbon-based new materials

The investigation of the electronic properties of graphene (single hexagonal layer of carbon atoms) has attracted a renewed interest after the development of recent techniques which permit to produce and manage single-layer (and also multilayer) samples of this materials. Nowadays truly atomic single-layer isolated samples are available as well as epitaxially grown graphene on substrates.

Fig. 1: electronic structure of graphene and Dirac-like dispersionA large interest, for its potential technological applications, concerns the investigation of optical and transport properties of both single-layer and multi-layered graphene, which are dominated by its so-called relativistic Dirac-like electronic structure (see Figure on the right).

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Competing orders in Iron based superconductors

In January 2008 a new family of superconductors has been discovered with FeAs layers. Iron is a magnetic ion and in traditional superconductors small amounts of magnetic impurities kill superconductivity so an iron based superconductor is at first sight surprising.

Tc has grow rapidly beyond 50K opening a new gate to high-Tc superconductivity. In addition the phase diagram has some similarities with the cuprates which suggest that understanding the superconductors from this new iron age can help to solve the mistery of the supercundoctors from the copper age.… Read the rest

Frustrated Phase Separation

A large variety of systems with competing short and long range interactions self-organizes in domain patterns as reviewed by Seul and Andelman. Examples range from magnetic systems (left figure A) to organic systems (left figure B).

Inhomogeneous states display a simple set of predominant morphologies like circular droplets and stripes in two-dimensional (2D) systems, and layers, cylindrical rods and spherical droplets in three-dimensional (3D) systems.… Read the rest

Polarons in organic single crystal FET’s

Organic field effect transistors (OFETs) are providing exciting prospects for potential applications in electronics. The active elements of these devices use “plastic” semiconductors, based on carbon and hydrogen. Among the advantages compared to classical silicon transistors, this new generation of components should combine mechanical flexibility, low weight, transparency and low cost. Enormous progress has been made to improve the performance of these devices through optimising the synthesis processes, drastically reducing the concentration of impurities present.… Read the rest

Unconventional antiferromagnetism due to Dzyaloshinskii-Moriya interactions

The relevance of antisymmetric superexchange interactions in spin Hamiltonians describing quantum antiferromagnetic (AF) systems has been acknowledged long ago by Dzyaloshinskii. Soon after, Moriya showed that such interactions arise naturally in perturbation theory due to the spin-orbit coupling in magnetic systems with low symmetry. Nowadays, a number of AF systems are known to belong to the class of Dzyaloshinskii-Moriya (DM) magnets, such as ?-Fe… Read the rest

Strongly Correlated Superconductivity: how can repulsion enhance Tc?

In conventional superconductors, the repulsive interaction between electrons opposes to phonon-mediated pairing. We have shown that even phonon-mediated superconductivity can be favoured by repulsion under suitable conditions which are realized in fullerenes.

Trivalent alkali-doped fullerenes are almost certainly electron-phonon superconductors, and their critical temperature can reach around 40K. There are however many experimental evidences that seem to exclude a simple BCS (or Migdal-Eliashberg) scenario, since electron-electron correlations are likely to play a central role.… Read the rest

Spin-orbit interaction and spintronics

One of the new frontiers in condensed matter physics is development and engineering of electronic devices which carrier “bit” informations in the spin degree of freedom of the electronc instead of their charge. This research line is called indeed “spintronics”. Within this context the spin-or

Rashba band-spilling and spin ordering: from J. Sinova et al., Phys. Rev. Lett. 92, 126603 (2004).

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Inhomogeneities in Cuprates

If the mechanism of high-Tc superconductivity is electronic, to understand the electronic excitation spectrum is as important as to understand phonons was important to develop BCS theory. In this regard charge and spin inhomogeneous states, often found in strongly correlated systems, are interesting because they can support new collective modes, “electronic phonons”, that would not be present in a weakly interacting fluid.… Read the rest

Unconventional electron-phonon interaction and nonadiabatic effects

The conventional understanding of the electron-phonon phenomenology in condensed matter strongly relies on the adiabatic assumption, i.e. that nuclei dynamics is much slower than the electron one. In solid crystals the validity of this assumption is usually related to the comparison of the phonon frequencies  with the Fermi energy EF. In conventional systems , assuring thus the reliability of the adiabatic assumption.… Read the rest