Quantum Control of Interacting Spins

Quantum decoherence is one of the most substantial challenges on the way to fullyfledged quantum technology. Noise mitigation based on dynamical control techniques, aside from error correction, is known to be another effective approach to protect qubits from decoherence. In this thesis, we studied the dynamics of a spin qubit interacting with a...

Long-lived coherence in driven many-spin systems: From two to infinite spatial dimensions

Long-lived coherences, emerging under periodic pulse driving in the disordered ensembles of strongly interacting spins, offer immense advantages for future quantum technologies, but the physical origin and the key properties of this phenomenon remain poorly understood. We theoretically investigate this effect in ensembles of different...

Excitation of unidirectional exchange spin waves by a nanoscale magnetic grating

Magnon spintronics is a prosperous field that promises beyond-CMOS technology based on elementary excitations of the magnetic order that act as information carriers for future computational architectures. Unidirectional propagation of spin waves is key to the realization of magnonic logic devices. However, previous efforts to enhance the...

Laser-induced ultrafast spin current pulses: A thermodynamic approach

The ultrafast demagnetization process allows for the generation of femtosecond spin current pulses. Here, we present a thermodynamic model of the spin current generation process, based on the chemical potential gradients as the driving force for the spin current. We demonstrate that the laser-induced spin current can be estimated by an easy...

Spin correlations in (Mn,Fe)2(P,Si) magnetocaloric compounds above Curie temperature

The longitudinal-field muon-spin relaxation (LF-μSR) technique was employed to study the spin correlations in (Mn,Fe)2(P,Si) compounds above the ferromagnetic transition temperature (TC). The (Mn,Fe)2(P,Si) compound under study is found to show itinerant magnetism. The standard deviation of the magnetic field distribution of electronic origin...

Exchange magnetic field torques in YIG/Pt bilayers observed by the spin-Hall magnetoresistance

The effective field torque of an yttrium-iron-garnet (YIG) film on the spin accumulation in an attached platinum (Pt) film is measured by the spin-Hall magnetoresistance (SMR). As a result, the magnetization direction of a ferromagnetic insulating layer can be measured electrically. Experimental transverse and longitudinal resistances are well...

Decoherence dynamics of a single spin versus spin ensemble

We study decoherence of central spins by a spin bath, focusing on the difference between measurement of a single central spin and measurement of a large number of central spins (as found in typical spin-resonance experiments). For a dilute spin bath, the single spin demonstrates Gaussian free-induction decay, in contrast to exponential decay...

Spin-glass dynamics in the two-dimensional Ising system rubidium copper cobalt fluoride (Rb2Cu1-xCoxF4)

Study of an attitude acquisition measurement technique using the ESA starmapper: Part I: Executive summary

The study deals with the rotational motion of a spin-stabilized spacecraft equipped with a V-slit sun sensor and the X-slit ESA starmapper. Assuming complete absence of an a priori attitude estimate, it is required to produce a rough estimate of the spacecraft attitude motion. It was assumed that sensor misalignments, external torques and...

Study of an attitude acquisition measurement technique using the ESA starmapper: Part two: final report

The study deals with the rotational motion of a spin-stabilized spacecraft equipped with a V-slit sun sensor and the X-slit ESA starmapper. Assuming complete absence of an a priori attitude estimate, it is required to produce a rough estimate of the spacecraft attitude motion. It was assumed that sensor misalignments, external torques and...