arXiv subjects

A T M Anishur Rahman

Publications and source records attributed to A T M Anishur Rahman.

4 recordsLinked to original sources

arXiv2026

Precessing magnetic particles as ac magnetic field sensors

Electromagnetic waves are widely used including in defense, biomedicine, and fundamental science. Their efficient detection determines how we communicate, defend against adversaries, diagnose diseases and perform search and rescue operations. In this article, exploiting the precession of a levitated magnetic particle in vacuum, we show that weak electromagnetic waves down to the femtotesla level can be detected. It is also shown that such a sensor has a large dynamic range over a millitesla, is continuously tunable over many gigahertz and can detect frequencies with sub-hertz resolutions. The direction of arrival of the incoming electromagnetic wave can also be found relatively easily.

physics.ins-det↗

arXiv2025

Nitrogen vacancy center in diamond-based Faraday magnetometer

The nitrogen vacancy (NV) center in diamond is a versatile color center used for magnetometry, quantum computing, and quantum communications. In this article, using a single laser beam as a pump and probe, we measure the spin states of the NV center using the Faraday effect and use such measurements to develop a novel magnetic field sensor. Using the spin-state-dependent effect on the left and right circularly polarized light, we probe and confirm the existence of spin-orbit coupling in the NV center at room temperature. The sensitivity of our magnetometer is $350~$nT/$\sqrt{Hz}$, limited by the background produced by the laser trapped inside the diamond. We argue that by using an optical cavity and a high-purity diamond, sensitivities in the femtotesla level can be achieved.

physics.app-ph↗

arXiv2020

Matter-wave interferometry using a levitated magnetic nanoparticle

The superposition principle is one of the bizarre predictions of quantum mechanics. Nevertheless, it has been experimentally verified using electrons, photons, atoms, and molecules. In this article, using a $20~$nm levitated ferromagnetic FePt nanoparticle, an exotic all optical spin polarization technique and the matter-wave interferometry, we show that a mesoscopic spatial Schrodinger cat can be created. Additionally, we argue that the maximum spatial separation between the delocalized wavepackets can be $25~μm$ and is significantly larger than the object itself.

cond-mat.mes-hall↗

arXiv2020

Large spatial Schrodinger cat using a levitated ferrimagnetic nanoparticle

The superposition principle is one of the main tenets of quantum mechanics. Despite its counter-intuitiveness, it has been experimentally verified using electrons, photons, atoms, and molecules. However, a similar experimental demonstration using a nano or a micro particle is non-existent. Here in this Letter, exploiting macroscopic quantum coherence and quantum tunneling, we propose an experiment using levitated magnetic nanoparticle to demonstrate such an effect. It is shown that the spatial separation between the delocalized wavepackets of a $20~$nm ferrimagnetic yttrium iron garnet (YIG) nanoparticle can be as large as $5~$$μ$m. We argue that this large spatial separation can be used to test different modifications such as collapse models to the standard quantum mechanics. Furthermore, we show that the spatial superposition of a core-shell structure, a YIG core and a non-magnetic silica shell, can be used to probe quantum gravity.

quant-ph↗