arXiv subjects

Daniel Tandeitnik

Publications and source records attributed to Daniel Tandeitnik.

9 recordsLinked to original sources

arXiv2026

Position measurement of a levitated particle with vectorial light

We develop a fully vectorial, semiclassical scattering formalism for optically levitated dipolar scatterers, expressed within the angular spectrum representation and applicable to arbitrary trapping-field configurations as well as to high--numerical-aperture focusing. Within this framework, we introduce the information radiation pattern to characterize the angular distribution of position-dependent information and use a Richards--Wolf projection of the scattered field onto the local-oscillator mode to quantify the resulting mode-matching efficiency, yielding experimentally realistic forward- and backward-detection efficiencies. As a worked example, we apply the formalism to a radially polarized trapping beam and confirm that the axial recoil heating rate is reduced relative to a conventional linearly polarized Gaussian tweezer. The theoretical framework is implemented in LevitationToolbox, an open-source Python package intended to support the design and optimization of near-Heisenberg-limited levitated optomechanical experiments.

physics.optics↗

arXiv2026

Heterodyne position detection of an optomechanical system

We report a heterodyne detection scheme for position readout of an optomechanical system, in particular an optically levitated particle, implemented via digital In-phase and Quadrature demodulation on a field-programmable gate array. Compared to the standard homodyne approach, the proposed method offers three key advantages: it remains robust in the presence of strong parasitic back-reflected fields that would otherwise prevent stable phase locking; it produces a signal linearly proportional to the particle displacement, eliminating phase-wrapping distortion; and its calibration factor is intrinsically immune to drifts in the optical power of the local oscillator or scattered field. We experimentally demonstrate and quantify all three advantages through simultaneous homodyne and heterodyne measurements on the same trapped particle. The proposed method can be used in any optomechanical system based on phase readout.

quant-ph↗

arXiv2026

All-optical saddle trap as a platform for mesoscopic quantum experiments

We investigate the quantum dynamics of a levitated nanoparticle in a structured light rotating saddle-like optical potential consisting of a superposition of Gaussian and Laguerre-Gauss modes with detuned frequencies. This rotating saddle trap offers unique opportunities for quantum experiments, such as reduced decoherence due to photon recoil and absorption, the possibility of large delocalization of the particle's center-of-mass motion, particle recovery protocols, the generation of motional entanglement and momentum squeezing. As an application, we show that this saddle-trap architecture enables force detection with sensitivity in the zepto-Newton regime.

quant-ph↗

arXiv2024

All-optical Saddle Trap

The superposition of frequency-shifted Laguerre-Gauss modes can produce a rotating saddle-like intensity profile. When spinning fast enough, the optical forces produced by this structured light saddle generate a dynamically stable equilibrium point capable of trapping nanoparticles in a high vacuum, akin to a Paul trap but with its unique characteristics. We analyze the stability conditions and center-of-mass motion, dynamics and cooling of a nanoparticle levitated in the optical saddle trap. We expect the optical saddle to find applications in levitated optomechanics experiments requiring fast parametric modulation and inverted squeezing potential landscapes.

physics.optics↗

arXiv2024

All electrical cooling of an optically levitated nanoparticle

We implement an all electrical controller for 3D feedback cooling of an optically levitated nanoparticle capable of reaching sub-Kelvin temperatures for the center of mass motion. The controller is based on an optimal policy where state estimation is made by delayed position measurements. The method offers a simplified path for pre-cooling and decoupling the transverse degrees of freedom of the nanoparticle. Numerical simulations show that in an improved setup with quantum limited detection, 3D ground state cooling and all electrical quantum control can be achieved.

quant-ph↗

arXiv2023

Perturbative nonlinear feedback forces for optical levitation experiments

Feedback control can be used to generate well-determined nonlinear effective potentials in an optical trap, a goal whose applications may range from non-equilibrium thermodynamics to the generation of non-Gaussian states of mechanical motion. Here, we investigate the action of an effective feedback-generated quartic potential on a levitated nanoparticle within the perturbation regime. The effects of feedback delay are discussed and predictions from the perturbation theory of a Brownian particle subjected to a quartic anharmonicity are experimentally verified.

quant-ph↗

arXiv2022

Evolving Quantum Circuits

We develop genetic algorithms for searching quantum circuits, in particular stabilizer quantum error correction codes. Quantum codes equivalent to notable examples such as the 5-qubit perfect code, Shor's code, and the 7-qubit color code are evolved out of initially random quantum circuits. We anticipate evolution as a promising tool in the NISQ era, with applications such as the search for novel topological ordered states, quantum compiling, and hardware optimization.

quant-ph↗

arXiv2022

QuGIT: a numerical toolbox for Gaussian quantum states

Simulating quantum states on a classical computer is hard, typically requiring prohibitive resources in terms of memory and computational power. Efficient simulation, however, can be achieved for certain classes of quantum states, in particular the so-called Gaussian quantum states of continuous variable systems. In this work we introduce QuGIT - a python numerical toolbox based on symplectic methods specialized in efficiently simulating multimode Gaussian states and operations. QuGIT is exact, requiring no truncation of Hilbert space, and provides a wide range of Gaussian operations on arbitrary Gaussian states, including unitaries, partial traces, tensor products, general-dyne measurements, conditional and unconditional dynamics. To illustrate the toolbox, several examples of usage relevant to quantum optics and optomechanics are described.

quant-ph↗

arXiv2021

Coherent Scattering-mediated correlations between levitated nanospheres

We explore entanglement generation between multiple optically levitated nanospheres interacting with a common optical cavity via the Coherent Scattering optomechanical interaction. We derive the many-particle Hamiltonian governing the unitary evolution of the system and show that it gives rise to quantum correlations among the various partitions of the setup, following a non-Markovian dynamics of entanglement birth, death and revivals. We also consider the effects of coupling the system to external environments and show that under reasonable experimental conditions entanglement between the mechanical modes can survive even at room temperature. Its dependence upon the number of nanoparticles, their initial temperature and coupling strength is studied. A numerical toolbox to simulate the closed and open dynamics of Gaussian optomechanical states and their informational measures is developed.

quant-ph↗