arXiv subjects

M. Boström

Publications and source records attributed to M. Boström.

At least 19 recordsLinked to original sources

arXiv2026

Beyond Attraction: A Novel Approach to Repulsive Casimir-Lifshitz Forces using heterogeneous off-stoichiometry in gapped metals

We uncover a novel physical mechanism that enables a switch between attractive and repulsive Casimir forces when a Teflon surface interacts with a new form of quantum material (i.e., gapped metal) surface across different liquid media. We demonstrate the discovery of a zero-frequency Casimir effect, which, for the first time, reveals the potential for quantum switching within nanometer distances-a scale previously thought to be unattainable. Hence, our results introduce a new method to induce phase (stoichiometry)-controlled attraction-repulsion transitions and achieving quantum levitation in a liquid medium by tuning the liquid environment. This study thus not only advances our understanding of quantum forces at the nanoscale via their correlation to dielectric properties of involved materials but also opens up exciting possibilities for their manipulation in novel ways, forming the basis towards innovative advancements in nanoscale technology.

cond-mat.mes-hall↗

arXiv2026

Inverse design for Casimir-Lifshitz force near heterogeneous gapped metal surface

The Casimir-Lifshitz force is calculated between a heterogeneous gapped metal surface and a silica sphere attached to an AFM cantilever tip. We demonstrate that heterogeneous surface patches with different off-stoichiometry surface properties lead to changes in the predicted distances for a specific force. This can incorrectly be interpreted as occurrences of surface roughness.

cond-mat.mtrl-sci↗

arXiv2025

Towards an understanding of dipole-dipole interactions in nonlocal media

We commence our study with review of dispersion interactions in electrolytes. We then reflect on how background media change atom-atom excited-state systems. To highlight the impact of nonlocal media, such as salt solutions, we predict that a new contribution to the resonance interaction energy emerges in a form $\propto e^{-κ_{\rm D} ρ}/ρ$. Here $κ_{\rm D}$ is the Debye length and $ρ$ is the distance between the atoms. This contribution vanishes at zero temperature, where a new term proportional to $1/ρ^4$ (similar to free space) occurs. This new term is dampened by the electrolyte at large distances, causing it to decrease much faster, proportional to $1/ρ^7$. The long-range electrolyte-induced resonance interaction at finite temperature may, in addition to the dominating van der Waals attraction (which goes as $1/ρ^6$), take part in the molecular formation of biological fluids.

quant-ph↗

arXiv2025

Nanorod Pair Complexes Manipulated via Magnetic Casimir Forces

Controlling nanoscale interactions to suppress aggregation from short-range attractive forces is a key problem in nanoengineering. Here, we demonstrate a route to modulate Casmir-Lifshitz interactions between anisotropic nanoparticles with the magnetic fluids. By semi-classical quantum electrodynamics, we study ground state dispersion forces for cylindrical dielectric nanorods made of polystyrene (PS), and zinc oxide (ZnO) embedded in toluene-based host media with gold-coated magnetite nanoparticles and also predict magnetic contributions to the non-retarded excited state interaction. The variation in magnetic permeability enables tuning between repulsive and attractive interaction and a thermally unstable and measurable magnetic Casimir traps are predicted between a pair of ZnO-PS nanoparticles whose equilibrium position can be modulated over an order of magnitude with a small variation in the size of the magnetite nanoparticle. This provides an alternative magnetic Casimir-effect pathway to reversibly tune quantum electromagnetic forces at the nanoscale for assembly and enhancement of colloidal stability.

cond-mat.mtrl-sci↗

arXiv2025

Trapping in a Casimir Force Set-Up Controlled by Solution Permeability

We have designed a system enabling tuning Casimir attraction/repulsion transitions between a polystyrene sphere attached to an atomic force microscope tip near a Teflon surface in a magnetic fluid mixture. Notably, the trapping distances can be changed by several orders of magnitude by changes in zero-frequency transverse electric contributions to the Casimir force. We demonstrate that this can be achieved via modifications in the average diameter for the magnetite particles while keeping the magnetite volume fractions fixed.

cond-mat.mtrl-sci↗

arXiv2025

Casimir Forces Across Magnetic Plasmas at Nuclear Separations

A theory and numerical findings are presented on the magnetic Casimir interaction that arises from vacuum fluctuations of the quantized field and its effects at the nuclear scale. We investigate how the zero-temperature Casimir effect at nuclear scales can generate the black-body temperatures required to induce a magnetic electron-positron plasma. The magnetic permeability of the plasma and any magnetic fields present influence the screened Casimir-Yukawa potentials between perfect conducting surfaces. We discuss implications for the magnetic Casimir-Yukawa potential, its screening length, and a magnetic permeability-dependent quantity that resembles the meson mass.

quant-ph↗

arXiv2024

Semi-Classical Electrodynamics and the Casimir Effect

From the late 1960s and onwards the groups of Barry Ninham and Adrian Parsegian, and their many collaborators, made a number of important contributions to theory and experiment of intermolecular forces. In particular, they explored the semi-classical theory: Maxwell's equations and Planck quantization of light $\rightarrow$ Lifshitz and Casimir interactions. We discuss some selected thought-provoking results from Ninham and his group. Some of the results have been conceived as controversial but, we dare, say never uninteresting.

quant-ph↗

arXiv2024

Axion Electrodynamics and the Casimir Effect

We present a concise review of selected parts of axion electrodynamics and its application to Casimir physics. We present the general formalism including the boundary conditions at a dielectric surface, derive the dispersion relation in the case where the axion parameter has a constant spatial derivative in the direction normal to the conducting plates, and calculate the Casimir energy for the simple case of scalar electrodynamics using dimensional regularization.

hep-th↗

arXiv2023

Understanding ice and water film formation on soil particles by combining DFT and Casimir-Lifshitz forces

Thin films of ice and water on soil particles play crucial roles in environmental and technological processes. Understanding the fundamental physical mechanisms underlying their formation is essential for advancing scientific knowledge and engineering practices. Herein, we focus on the role of the Casimir-Lifshitz force, also referred to as dispersion force, in the formation and behavior of thin films of ice and water on soil particles at 273.16 K, arising from quantum fluctuations of the electromagnetic field and depending on the dielectric properties of interacting materials. We employ the first-principles density functional theory (DFT) to compute the dielectric functions for two model materials, CaCO$_3$ and Al$_2$O$_3$, essential constituents in various soils. These dielectric functions are used with the Kramers-Kronig relationship and different extrapolations to calculate the frequency-dependent quantities required for determining forces and free energies. Moreover, we assess the accuracy of the optical data based on the DFT to model dispersion forces effectively, such as those between soil particles. Our findings reveal that moisture can accumulate into almost micron-sized water layers on the surface of calcite (soil) particles, significantly impacting the average dielectric properties of soil particles. This research highlights the relevance of DFT-based data for understanding thin film formation in soil particles and offers valuable insights for environmental and engineering applications.

cond-mat.mtrl-sci↗

arXiv2023

A knob to tune the Casimir-Lifshitz force with gapped metals

The Casimir-Lifshitz interaction, a long-range force that arises between solids and molecules due to quantum fluctuations in electromagnetic fields, has been widely studied in solid-state physics. The degree of polarization in this interaction is influenced by the dielectric properties of the materials involved, which in turn are determined by factors such as band-to-band transitions, free carrier contributions, phonon contributions, and exciton contributions. Gapped metals, a new class of materials with unique electronic structures, offer the potential to manipulate dielectric properties and, consequently, the Casimir-Lifshitz interaction. In this study, we theoretically investigate the finite temperature Casimir-Lifshitz interaction in La$_3$Te$_4$-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. We predict measurable corrections due to stoichiometry on the predicted Casimir force between a La$_3$Te$_4$ surface and a gold sphere, attached to an atomic force microscopy tip.

cond-mat.mtrl-sci↗

arXiv2023

Secondary ice growth mechanism for ice nuclei in the atmosphere

The study of atmospheric ice nuclei is vital for understanding the formation of precipitation and the development of cloud systems as it reveals how these tiny particles grow. A mechanism of such growth when the nuclei are in a mixed ice/water phase and quantum vacuum fluctuation-induced Casimir-Lifshitz interaction highlights the complexity and interconnection of the atmospheric processes with quantum theory. Initially of the order of $0.1\sim10\rmμm$ in size, atmospheric ice nuclei can expand by the accumulation of water molecules from the surrounding water vapor.

cond-mat.mtrl-sci↗

arXiv2023

Different pathways to anomalous stabilization of ice layers on methane hydrates

We explore the Casimir-Lifshitz free energy theory for surface freezing of methane gas hydrates near the freezing point of water. The theory enables us to explore different pathways, resulting in anomalous (stabilising) ice layers on methane hydrate surfaces via energy minimization. Notably, we will contrast the gas hydrate material properties, under which thin ice films can form in water vapor, with those required in the presence of liquid water. It is predicted that methane hydrates in water vapor near the freezing point of water nucleate ice films but not water films.

cond-mat.mtrl-sci↗

arXiv2022

Effect of excess charge carriers and fluid medium on the magnitude and the sign of the Casimir-Lifshitz torque

Last year, we reported a perturbative theory of the Casimir-Lifshitz torque between planar biaxially anisotropic materials in the retarded limit [Phys. Rev. Lett. {\bf 120}, 131601 (2018)], which is applied here to study the change of sign and magnitude of the torque with separation distance in biaxial black phosphorus having excess charge carriers. The study is carried out both in vacuum as well as in a background fluid medium. The presence of extra charge carriers and that of an intervening fluid medium are both found to promote enhancement of the magnitude of the torque between identical slabs. The degree of enhancement of the magnitude of torque increases not only with an increased carrier concentration but also with separation distance. In the non-identical case when different planes of anisotropic black phosphorus face each other, owing to the non-monotonic characteristic of the sign-reversal effect of the torque, the enhancement by carrier addition and intervening medium also becomes non-monotonic with distance. In the presence of a background medium, the non-monotonic degree of enhancement of the torque with distance is observed even between identical slabs.

cond-mat.mes-hall↗

arXiv2018

Impact of effective polarisability models on the predicted release dynamics of CH$_4$ and CO$_2$ from premelted ice

We present a theory for Casimir--Polder forces acting on greenhouse gas molecules dissolved in a thin water film. Such a nanosized film has recently been predicted to arise on th surface of melting ice as stabilized by repulsive Lifshitz forces. We show that different models for the effective polarizability of greenhouse gas molecules in water lead to different predictions for how Casimir--Polder forces influence the extraction of CH$_4$ and CO$_2$ molecules from the melting ice surface. In the most intricate model of a finite-sized molecule inside a cavity, dispersion potentials push the methane molecules towards the ice surface whereas the carbon dioxide typically will be attracted towards the closest interface (ice or air). Previous models for effective polarizability had suggested that CO$_2$ would also be pushed towards the ice surface. Release of greenhouse gas molecules from the surface of melting ice can potentially influence climate greenhouse effects.

physics.ao-ph↗

arXiv2016

Effects of van der Waals forces and salt ions on the growth of water films on ice and the detachment of CO$_2$ bubbles

We study the effect of salts on the thickness of wetting films on melting ice and interactions acting on CO$_2$ bubble near ice-water and vapor-water interfaces. Governing mechanisms are the Lifshitz and the double-layer interactions in the respective three-layer geometries. We demonstrate that the latter depend on the Casimir--Polder interaction of the salt ions dissolved in water with the respective ice, vapour and CO$_2$ interfaces, as calculated using different models for their effective polarizability in water. Significant variation in the predicted thickness of the equilibrium water film is observed for different salt ions and when using different models for the ions' polarizabilities. We find that CO$_2$ bubbles are attracted towards ice-water interface and repelled from the vapor-water interface

cond-mat.soft↗

arXiv2016

The influence of Lifshitz forces and gas on premelting of ice within porous materials

Premelting of ice within pores in earth materials is shown to depend on the presence of vapor layers. For thick vapor layers between ice and pore surfaces, a nanosized water sheet can be formed due to repulsive Lifshitz forces. In the absence of vapor layers, ice is inhibited from melting near pore surfaces. In between these limits, we find an enhancement of the water film thickness in silica and alumina pores. In the presence of metallic surface patches in the pore, the Lifshitz forces can dramatically widen the water film thickness, with potential complete melting of the ice surface.

cond-mat.soft↗

arXiv2015

Non-Perturbative Theory of Dispersion Interactions

Some open questions exist with fluctuation-induced forces between extended dipoles. Conventional intuition derives from large-separation perturbative approximations to dispersion force theory. Here we present a full non-perturbative theory. In addition we discuss how one can take into account finite dipole size corrections. It is of fundamental value to investigate the limits of validity of the perturbative dispersion force theory.

quant-ph↗

arXiv2014

Finite size dependent dispersion potentials between atoms and ions dissolved in water

A non-expanded theory is used for dispersion potentials between atoms and ions dissolved in a medium. The first-order dispersion interaction between two atoms in an excited state must account for the fact that the two atoms are coupled via the electromagnetic field and must include effects from background media, retardation and finite size. We show that finite-size corrections when two particles are close change the dispersion interactions in water by several orders of magnitude. We consider as four illustrative examples helium atoms, krypton atoms, phosphate ions, and iodide ions. We demonstrate that, due to large cancellation effects, retardation dominates the interaction for helium atom pairs in an isotropic excited state down to the very small atom-atom separations where finite-size corrections are also important

physics.atom-ph↗