arXiv subjects

Alessandro Cerioni

Publications and source records attributed to Alessandro Cerioni.

7 recordsLinked to original sources

arXiv2026

Iterative approach for high-quality binary intensity hologram generation in augmented reality applications

Binary amplitude spatial light modulators, such as digital micromirror devices (DMDs), are increasingly relevant for computer generated holography due to their high refresh rates, low cost, and due to the emergence of subwavelength pixel architectures. However, the binary constraint limits the reconstruction quality, as conventional approaches rely on a binarization applied as a final step after hologram computation which leads to reduced efficiency and contrast. We introduce an iterative estimation approach for the generation of off axis binary amplitude holograms, in which the binarization constraint is applied at each iteration. We validate the approach through numerical simulations and experimental reconstruction using a DMD based optical setup. Quantitative and qualitative comparisons with random superposition and Gerchberg Saxton methods demonstrate significant improvements in image contrast, light efficiency, and reconstruction fidelity, with comparable computational cost. The proposed method provides a practical route toward high quality CGH using binary modulators and supports emerging applications requiring high speed and high resolution holographic projection.

physics.optics↗

arXiv2026

Zero-Order Diffraction Suppression in Full Field-of-View Computer Generated Holography: A Camera In the Loop Interferometric Approach

We introduce a novel interferometric approach for suppressing zero-order diffraction (ZOD) in phase-only computer-generated holography. The technique relies on the destructive interference between the zeroth-order light and a suppression beam in a plane optically conjugated to the spatial light modulator (SLM). A camera-in-the-loop (CITL) calibration procedure retrieves the optimal pixel-wise phase map that cancels out the ZOD component with high precision, while preserving the full modulation depth of the SLM. Experimental demonstrations on point-cloud and 2D/3D holograms achieve up to 99% suppression of the ZOD intensity, without loss of image quality or field of view. Once calibrated, the correction can be applied to any hologram without recomputation, enabling real-time operation and robust performance over time. This method removes a long-standing barrier to the practical deployment of full-field holography, facilitating the development of compact, high-fidelity holographic engines for augmented and mixed reality displays.

physics.optics↗

arXiv2015

Identification of Resonant States via the Generalized Virial Theorem

The numerical extraction of resonant states of open quantum systems is usually a difficult problem. Regularization techniques, such as the mapping to complex coordinates or the addition of Complex Absorbing Potentials are typically employed, as they render resonant wavefunctions localized and therefore normalizable. Physically relevant metastable states have energies that do not depend on the chosen regularization method. Their identification therefore involves cumbersome comparisons between multiple regularised calculations, often performed graphically, which require fine-tuning and specific intuition to avoid approximated, if not wrong, results. In this Letter, we define an operator that explicitly measures such invariance, valid for any arbitrary mapping of spatial coordinates. Resonant states of the system can eventually simply be identified evaluating the expectation value of this operator. Our method eases the extraction of resonant states even for numerical potentials that are difficult to scale to complex coordinates, and avoids the need for ad hoc complex absorbing potentials. We provide explicit evidence of our findings discussing one-dimensional case-studies,also in the presence of external electric fields.

cond-mat.mtrl-sci↗

arXiv2013

Accurate Complex Scaling of Three Dimensional Numerical Potentials

The complex scaling method, which consists in continuing spatial coordinates into the complex plane, is a well-established method that allows to compute resonant eigenfunctions of the time-independent Schroedinger operator. Whenever it is desirable to apply the complex scaling to investigate resonances in physical systems defined on numerical discrete grids, the most direct approach relies on the application of a similarity transformation to the original, unscaled Hamiltonian. We show that such an approach can be conveniently implemented in the Daubechies wavelet basis set, featuring a very promising level of generality, high accuracy, and no need for artificial convergence parameters. Complex scaling of three dimensional numerical potentials can be efficiently and accurately performed. By carrying out an illustrative resonant state computation in the case of a one-dimensional model potential, we then show that our wavelet-based approach may disclose new exciting opportunities in the field of computational non-Hermitian quantum mechanics.

cond-mat.mtrl-sci↗

arXiv2012

Efficient and accurate solver of the three-dimensional screened and unscreened Poisson's equation with generic boundary conditions

We present an explicit solver of the three-dimensional screened and unscreened Poisson's equation which combines accuracy, computational efficiency and versatility. The solver, based on a mixed plane-wave / interpolating scaling function representation, can deal with any kind of periodicity (along one, two, or three spatial axes) as well as with fully isolated boundary conditions. It can seamlessly accommodate a finite screening length, non-orthorhombic lattices and charged systems. This approach is particularly advantageous because convergence is attained by simply refining the real space grid, namely without any adjustable parameter. At the same time, the numerical method features O(N log N) scaling of the computational cost (N being the number of grid points) very much like plane-wave methods. The methodology, validated on model systems, is tailored for leading-edge computer simulations of materials (including ab initio electronic structure computations), but it might as well be beneficial for other research domains.

cond-mat.mtrl-sci↗

arXiv2010

Cosmological Perturbations in the "Healthy Extension'' of Horava-Lifshitz gravity

We study linear cosmological perturbations in the ``healthy extension'' of Horava-Lifshitz gravity which has recently been analyzed \cite{BPS2}. We find that there are two degrees of freedom for scalar metric fluctuations, but that one of them decouples in the infrared limit. Also, for appropriate choices of the parameters defining the Lagrangian, the extra mode can be made well-behaved even in the ultraviolet.

hep-th↗

arXiv2010

Cosmological Perturbations in the Projectable Version of Horava-Lifshitz Gravity

We consider linear perturbations about a homogeneous and isotropic cosmological background in the projectable version of Hořava-Lifshitz gravity. Starting from the action for cosmological perturbations, we identify the canonically normalized fluctuation variables. We find that - in contrast to what happens in the non-projectable version of the theory - the extra scalar cosmological perturbation mode is already dynamical at the level of linear perturbations. For values of the parameter $λ$ in the range $1/3 < λ< 1$, the extra mode is ghost-like, for values $1 < λ$ and $λ< 1/3$ it is tachyonic. This indicates a problem for the projectable version of Hořava-Lifshitz gravity.

hep-th↗