Article
Optics
K. Wongcharoenbhorn, C. Koller, T. M. Fromhold, W. Li
Summary: We investigate the thermal Casimir-Polder (CP) potential of 87Rb atoms in Rydberg nS-states near single- and double-layer graphene, and briefly explore the lifetimes near graphene-hexagonal boron nitride (hBN) multilayered structures. The dependence of the CP potential on parameters such as atom-surface distance, temperature, principal quantum number n, and graphene Fermi energy are studied. We find that the CP potential is dominated by nonresonant and evanescent-wave terms in the nonretarded regime, while exhibiting spatial oscillations in the retarded regime.
Article
Physics, Multidisciplinary
Valentin Gebhart, Juliane Klatt, Gunther Cronenberg, Hanno Filter, Stefan Yoshi Buhmann
Summary: This study predicts a repulsive Casimir-Polder-type dispersion interaction between a single neutron and a metal or dielectric surface, due to the intrinsic magnetic moment of the neutron. The interaction is found to be considerably smaller than the standard atom-surface Casimir-Polder force, but comparable to the gravitational potential of the same surface, which should be considered in future neutron interference experiments.
NEW JOURNAL OF PHYSICS
(2021)
Article
Optics
Danilo T. Alves, Lucas Queiroz, Edson C. M. Nogueira, N. M. R. Peres
Summary: This paper investigates the lateral van der Waals (vdW) force between a neutral polarizable point particle and a perfectly conducting infinite cylinder. It is found that under certain conditions, including particle orientation, anisotropy, and cylinder curvature, the lateral vdW force can exhibit a repulsive behavior, pushing the particle away from the cylinder. This study extends the understanding of the sign inversion in lateral forces and the characteristics of lateral vdW forces.
Article
Physics, Particles & Fields
Saptarshi Saha, Chiranjeeb Singha, Arpan Chatterjee
Summary: The paper examines a two-atom system moving through a circular ring at ultra-relativistic speed and interacting weakly with quantum fields. The study calculates the second-order energy shift of entangled states, revealing the presence of resonance Casimir-Polder interaction in a circular trajectory. The results show that the energy shift is delayed due to interactions with the fields, and this phenomenon can be observed through the polarization transfer technique.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Multidisciplinary Sciences
Galina L. Klimchitskaya, Constantine C. Korikov, Vladimir M. Mostepanenko, Oleg Yu. Tsybin
Summary: This study investigates the out-of-thermal-equilibrium Casimir-Polder force between nanoparticles and dielectric substrates coated with gapped graphene using the Dirac model and the polarization tensor formalism. The results show that the presence of a substrate can increase the magnitude of the nonequilibrium force. The temperature of the graphene-coated substrate also affects the force magnitude.
Article
Materials Science, Multidisciplinary
G. L. Klimchitskaya, V. M. Mostepanenko, O. Yu. Tsybin
Summary: In this study, the nonequilibrium Casimir-Polder force between a nanoparticle and a graphene sheet kept at different temperatures was examined using the formalism of the polarization tensor in the framework of a Dirac model. The results demonstrate that the magnitude of the force increases with the temperature of the graphene sheet. The impact of nonequilibrium conditions on the force becomes smaller at larger separations. Our findings reveal that for a graphene sheet with a lower temperature than the environment, the attractive Casimir-Polder force vanishes at a specific separation distance and becomes repulsive at larger distances. This effect has potential applications in fundamental graphene research and force control in bioelectronic microdevices.
Article
Optics
Joseph Durnin, Juliane Klatt, Robert Bennett, Stefan Yoshi Buhmann
Summary: Casimir-Polder interactions cause energy and momentum exchange between microscopic and macroscopic bodies. However, the dynamics of these effects have not been experimentally investigated because currently attainable atomic velocities are dominated by static effects. In this study, a more easily realizable setup involving a moving atom between two stationary plates is analyzed to establish the spectroscopic Casimir-Polder effects on the atom and their velocity dependence.
Article
Astronomy & Astrophysics
Kacper Debski, Piotr T. Grochowski, Andrzej Dragan
Summary: By using the Unruh-DeWitt detector model, we found an interesting relation between the excitation rate of an atom and the Casimir-Polder energy, providing an alternative method for investigating the Casimir-Polder effect.
Article
Astronomy & Astrophysics
Nail Khusnutdinov, Natalia Emelianova
Summary: The study investigated the low-temperature expansion of the Casimir-Polder free energy for an atom and graphene using the Poisson representation. The analysis extended to different relations between chemical potential mu and mass gap parameter m, with a focus on the dependence of graphene conductivities on mu and m. Results revealed the thermal correction for mu>m resembling T-2, and differing behavior for mu<m or mu
Article
Materials Science, Multidisciplinary
P. P. Abrantes, G. Bastos, D. Szilard, C. Farina, F. S. S. Rosa
Summary: The study investigates the resonance energy transfer rate between two quantum emitters near a suspended graphene sheet in vacuum under the influence of an external magnetic field. It shows that graphene's extraordinary magneto-optical response allows for active control and tunability of the RET even at room temperature. The RET rate is extremely sensitive to small variations of the applied magnetic field and can be tuned up to six orders of magnitude for realistic values of magnetic field.
Article
Chemistry, Physical
Huabing Shu, Xiaomei Liu
Summary: In this study, the effects of surface modification (fluorination) on the electronic and optical properties of graphene/h-BN heterobilayer were theoretically explored. The results show that after fluorination, the heterobilayer adopts a diamane-like configuration, which remains stable at high temperatures. The fluorinated graphene/h-BN is found to be a wide-gap direct semiconductor, and its optical absorption spectrum is dominated by discrete excitonic peaks with a large exciton binding energy. The interfacial atom bonding, particularly the C-B bonding configuration, significantly affects the electronic and optical properties. Therefore, fluorination-induced interfacial sp(3) atom bonding could play a crucial role in tuning the optoelectronic performance of graphene/h-BN heterobilayers.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
M. Bostrom, M. R. Khan, H. R. Gopidi, I. Brevik, Y. Li, C. Persson, O. Malyi
Summary: In this study, we investigate the finite temperature Casimir-Lifshitz interaction in La3Te4-based gapped metal systems with varying off-stoichiometry levels. We demonstrate that off-stoichiometric effects in gapped metals can be used to control the magnitude and, in some cases, even the sign of Casimir-Lifshitz interactions.
Article
Thermodynamics
Hao Wu, Jianshu Gao, Yangheng Xiong, Quanli Zhu, Yanan Yue
Summary: By tuning the thermal conductance of graphene-polyethylene composites through the inclination angle and curvature of graphene, the thermal performance can be optimized. An increase in inclination angle above 60 degrees enhances the overall thermal conductance due to planar heat transfer effects.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Optics
Wang Han, Lei Yazhou, Han Jianfei
Summary: Theoretical study on magnetic field dependence of nonreciprocal absorption effect for composite microstructure is conducted. Graphene conductivity calculation models are analyzed and summarized, and electrical conductivities and dielectric constants of graphene are discussed and compared based on different theoretical models. The most suitable calculation model is chosen, and the influence of the chemical potential on the refractive index of graphene under external magnetic field is compared and discussed.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Physics, Condensed Matter
Jing Liu, Xiu Wu, You Xie, Jian-Min Zhang
Summary: The electronic structures and optical properties of graphene/phosphorene heterostructures and their response to external electric fields were investigated through first-principles calculations. It was found that an external electric field can effectively control the band structure of the heterostructure. The heterostructures showed anisotropic optical properties, and various optical parameters changed according to the direction and intensity of the external electric field. This research provides a theoretical basis for the potential application of graphene/phosphorene heterostructures in nanoelectronics and optoelectronics-based devices.
MICRO AND NANOSTRUCTURES
(2022)
Article
Physics, Applied
Oliver J. Trojak, Sean Gorsky, Connor Murray, Fabrizio Sgrignuoli, Felipe A. Pinheiro, Luca Dal Negro, Luca Sapienza
Summary: Enhancing light-matter interactions on a chip using aperiodic structures allows for efficient visible light confinement and higher quality factors for optical resonances. This approach shows potential applications in active nanophotonic devices, improving the understanding of fundamental physical properties of light-emitting systems.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Rfaqat Ali, R. S. Dutra, F. A. Pinheiro, P. A. Maia Neto
Summary: A novel scheme is proposed for all-optical enantioselection and sorting of single multipolar chiral microspheres based on optical pulling forces from two non-collinear, non-structured, circularly polarized light sources. This method allows for external control by varying the angle between incident wavevectors for fine-tuning of chiral indices for enantioselection, achieving all-optical sorting of chiral microspheres with arbitrarily small chiral parameters.
Article
Physics, Multidisciplinary
Tarik P. Cysne, Marcio Costa, Luis M. Canonico, M. Buongiorno Nardelli, R. B. Muniz, Tatiana G. Rappoport
Summary: Recent research has shown that TMD monolayers in the 2H structural phase exhibit large orbital Hall conductivity plateaus within their energy band gaps, with their spin Hall conductivities vanishing. The valley Hall effect in these systems also generates a transverse flow of orbital angular momentum, making it experimentally challenging to distinguish between the two effects. However, it has been found that a 2H-MoS2 bilayer can act as an orbital Hall insulator, showing a significant orbital Hall effect in the absence of both spin and valley Hall effects.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
R. Ali, R. S. Dutra, F. A. Pinheiro, P. A. Maia Neto
Summary: The study theoretically investigated optical tweezing of gain-functionalized microspheres using a highly focused single beam in the nonparaxial regime. Optical gain was found to play a crucial role in optical manipulation, especially in trapping large refractive index and plasmonic particles, with the ability to manipulate the equilibrium position of tweezed particles by varying the gain value through changing the pump power. This finding opens new pathways for gain-assisted optomechanics, particularly in facilitating optical trapping and manipulation of plasmonic nanoparticles with potential applications in self-assembling of nanoparticle suspensions and on a chip.
Article
Astronomy & Astrophysics
Daniela Szilard, Patricia P. Abrantes, Felipe A. Pinheiro, Felipe S. S. Rosa, Carlos Farina, Wilton J. M. Kort-Kamp
Summary: This study examines optical forces on oscillating dipoles near a phase change vanadium dioxide film and demonstrates the impact of thermal hysteresis on the behavior of optical forces. The research shows that by heating or cooling the film, the forces on the dipoles can switch from attractive to repulsive, highlighting the potential for controlling light-matter interactions using thermochromic materials.
Article
Nuclear Science & Technology
Rodrigo Costa Diniz, Felipe Siqueira de Souza da Rosa, Alessandro da Cruz Goncalves
Summary: This paper analyzes situations in Molten Salt Reactors where transit time cannot be trivially calculated and provides analytical solutions and a numerical method. The numerical method is validated by comparing its solutions with the analytical ones. The influence of the detailed calculation of transit time on point kinetics equations is checked, determining which cases are most sensitive to the exact calculation of transit time.
ANNALS OF NUCLEAR ENERGY
(2022)
Article
Physics, Condensed Matter
J. H. Nascimento, F. A. Pinheiro, M. B. Silva Neto
Summary: We develop a rigorous field-theoretical approach to study spontaneous emission in liquid crystals, providing insights into the role of phase transitions and making quantitative predictions. We also determine the orientation of the emitter's dipole moment relative to the liquid crystal director, which can be used to achieve directionality of emitted radiation.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Physics, Multidisciplinary
Marcio Costa, Bruno Focassio, Luis M. Canonico, Tarik P. Cysne, Gabriel R. Schleder, R. B. Muniz, Adalberto Fazzio, Tatiana G. Rappoport
Summary: Monolayers of transition metal dichalcogenides (TMDs) in the 2H structural phase have been classified as higher-order topological insulators (HOTIs), protected by C-3 rotation symmetry. The insulating gap of TMDs also exhibits an orbital Hall plateau characterized by an orbital Chern number. By using density functional theory, the correlation between these two phenomena in TMD monolayers in two structural phases (2H and 1T) is explored. The findings show that the HOTI phase is accompanied by an orbital Hall effect, which has potential implications for orbitronics and spin orbitronics.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Tarik P. Cysne, Filipe S. M. Guimaraes, Luis M. Canonico, Marcio Costa, Tatiana G. Rappoport, R. B. Muniz
Summary: In this study, nanoribbons made of transition metal dichalcogenides (TMDs) exhibit a significant orbital magnetoelectric effect (OME) when an electric field is applied along the ribbons' axis. The accumulation of orbital angular momentum mainly occurs near the edges of the nanoribbons, resulting from both orbital Hall effect (OHE) and OME. The OHE accumulation is approximately half in 1L nanoribbons compared to 2L nanoribbons, and the OME vanishes in 2L nanoribbons due to spatial inversion symmetry.
Article
Materials Science, Multidisciplinary
Y. Muniz, P. P. Abrantes, L. Martin-Moreno, F. A. Pinheiro, C. Farina, W. J. M. Kort-Kamp
Summary: This study investigates the spontaneous decay of a quantum emitter near single-walled carbon nanotubes and graphene-coated wires. The results show enhanced generation of entangled states in single-walled carbon nanotubes and predict significantly higher emission rates compared to free space. The findings provide a basis for a new material platform for on-chip quantum information technologies.
Article
Materials Science, Multidisciplinary
Tarik P. Cysne, Sayantika Bhowal, Giovanni Vignale, Tatiana G. Rappoport
Summary: The study of the orbital Hall effect in bilayers of transition metal dichalcogenides provides insights into the interlayer coupling and the role of different descriptions of the orbital angular momentum operator in understanding this phenomenon. The results support recent theoretical predictions on OHE in two-dimensional materials.
Article
Optics
F. Impens, F. M. D'Angelis, F. A. Pinheiro, D. Guery-Odelin
Summary: In this study, a time-scaling technique is introduced to enhance the performances of quantum control protocols in nonHermitian systems, resulting in a significant improvement of quantum fidelity without additional couplings. The application of this technique to quantum-state transfers in two- and three-level open quantum systems is discussed, along with the derivation of the quantum speed limit in a system governed by a non-Hermitian Hamiltonian. Interestingly, it is shown that with the appropriate driving, the time-scaling technique maintains the optimality of the quantum speed with respect to the quantum speed limit while reducing the damping of the quantum-state norm.
Article
Materials Science, Multidisciplinary
M. Prado, F. Sgrignuoli, Y. Chen, L. Dal Negro, F. A. Pinheiro
Summary: This study investigates the spatial decay and temporal localization properties of quasimodes in two-dimensional Vogel spirals, revealing the coexistence of three distinctive decay types and the characterization of Gaussian decay as the most localized quasimodes. The findings are supported by no-fitting analysis of localization maps and calculations of electric fields in real space, providing direct evidence of algebraic spatial decay of critical quasimodes. The existence of both long-lived and spatially localized quasimodes in Vogel spirals could potentially offer novel optical functionalities for applications in light sources and sensing devices.
Article
Materials Science, Multidisciplinary
P. P. Abrantes, Tarik P. Cysne, D. Szilard, F. S. S. Rosa, F. A. Pinheiro, C. Farina
Summary: In this study, quantum reflection of different atoms by graphene family materials under external electric field and light was theoretically investigated. The results showed distinctive signatures of topological phase transitions in quantum reflection probability, which can be highly tunable by external agents, providing a new method for probing the topological phase transitions of graphene family materials.
Article
Materials Science, Multidisciplinary
W. J. M. Kort-Kamp, F. J. Culchac, F. S. S. Rosa, C. Farina, Rodrigo B. Capaz, F. A. Pinheiro
Summary: This study investigates the electromagnetic local density of states near a twisted bilayer graphene deposited on an isotropic substrate. The conductivity of the TBG shows a nontrivial dependence on the twist angle, leading to moire pattern-dependent quantum emission. The presence or absence of surface plasmon polaritons explains the impressive variation in LDOS at specific twist angles compared to monolayer graphene.