A quantum magnetic RC circuit

We propose a setup that is the spin analog of the charge-based quantum RC circuit. We define and compute the spin capacitance and the spin resistance of the circuit for both ferromagnetic (FM) and antiferromagnetic (AF) systems. We find that the antiferromagnetic setup has universal properties, but the ferromagnetic setup does not. We discuss how to use the proposed setup as a quantum source of spin excitations, and put forward a possible experimental realization using ultracold atoms in optical lattices

Josephson and Persistent Spin Currents in Bose-Einstein Condensates of Magnons

Using the Aharonov-Casher (A-C) phase, we present a microscopic theory of the Josephson and persistent spin currents in quasi-equilibrium Bose-Einstein condensates (BECs) of magnons in ferromagnetic insulators. Starting from a microscopic spin model that we map onto a Gross-Pitaevskii Hamiltonian, we derive a two-state model for the Josephson junction between the weakly coupled magnon-BECs. We then show how to obtain the alternating-current (ac) Josephson effect with magnons as well as macroscopic quantum self-trapping in a magnon-BEC. We next propose how to control the direct-current (dc) Josephson effect electrically using the A-C phase, which is the geometric phase acquired by magnons moving in an electric field. Finally, we introduce a magnon-BEC ring and show that persistent magnon-BEC currents flow due to the A-C phase. Focusing on the feature that the persistent magnon-BEC current is a steady flow of magnetic dipoles that produces an electric field, we propose a method to directly measure it experimentally.Comment: 8 pages, 6 figures, updated into published versio

Frequency dependent transport through a spin chain

Motivated by potential applications in spintronics, we study frequency dependent spin transport in nonitinerant one-dimensional spin chains. We propose a system that behaves as a capacitor for the spin degree of freedom. It consists of a spin chain with two impurities a distance $d$ apart. We find that at low energy (frequency) the impurities flow to strong coupling, thereby effectively cutting the chain into three parts, with the middle island containing a discrete number of spin excitations. At finite frequency spin transport through the system increases. We find a strong dependence of the finite frequency characteristics both on the anisotropy of the spin chain and the applied magnetic field. We propose a method to measure the finite-frequency conductance in this system

Een huis om te bewaren. De ontstaansgeschiedenis 1840-1848 van het strafcellengebouw gelegen ten noorden van het Pesthuis in Leiden, in de volksmond: de Vrouwengevangenis

In the House of Detention in Amsterdam, completed in 1850, the thermo-ventilation system used there seems to result in an oppressive climate, especially in summer. In his letter of July 20, 1851 Warnsinck states that this problem had also been noticed in the model prison of Pentonville, where the cell windows were made to open again in such a way that communication through the open windows was nevertheless impossible. As an additional advantage he remarks that in summer there is no need to light a fire, so it is cheaper, too…! He encloses a sketch of a solution, so that in Amsterdam the windows can also be opened again. In 1843 the architect Warnsinck and the engineer Van Gendt were sent by the Dutch government to England and Scotland to study the latest developments in prison design and construction. On their return they reported very positively about the ‘Pennsylvanian system’, and especially about its most recent culmination in the model prison of Pentonville in North-London. Shortly thereafter Warnsinck and van Gendt were commissioned with the design of the new prisons in Amsterdam (1850) and Utrecht (1853), whereby they followed the Pentonville-model very closely. At the same time Warnsinck was also appointed as the first architect-adviser to the Department of Justice, with the special task of introducing the principles of the ‘cellular system’ in the design of other prisons in the Netherlands. As such he advised on the design of a small complex of disciplinary cells in the Military Prison, housed in the former Pesthuis of Leyden. In his proposals for this very small building he also stuck very closely to the Pentonville model, including the system of ‘thermoventilation’. The eventual building, completed in 1848, shows that his advice was only partially followed up by the responsible authorities. Architecturally the building showed many features of Pentonville to the smallest details, however the thermo-ventilation system was left out and was realised for the first time in the Amsterdam Prison. Despite this deficiency the Leyden prison can be considered as the prototype of the ‘cellular prison’ in the Netherlands

Magnetic texture-induced thermal Hall effects

Magnetic excitations in ferromagnetic systems with a noncollinear ground state magnetization experience a fictitious magnetic field due to the equilibrium magnetic texture. Here, we investigate how such fictitious fields lead to thermal Hall effects in two-dimensional insulating magnets in which the magnetic texture is caused by spin-orbit interaction. Besides the well-known geometric texture contribution to the fictitious magnetic field in such systems, there exists also an equally important contribution due to the original spin-orbit term in the free energy. We consider the different possible ground states in the phase diagram of a two-dimensional ferromagnet with spin-orbit interaction: the spiral state and the skyrmion lattice, and find that thermal Hall effects can occur in certain domain walls as well as the skyrmion lattice

Musis Sacrum : muziekvereniging in Leiden, 1828-1929

Musis Sacrum was een vereniging speciaal voor muziekliefhebbers uit Leiden, met eigen koor en orkest. Opgericht in 1828, te gronde gegaan in 1929. Het had vanaf 1870 een prachtig paviljoen in het Leidse Plantsoen. Toen had het geen eigen orkest en koor meer. Jubileumjaren worden getelf vanaf 1828 én vanaf 1870. Of de sociëteit van 1870 een voortzetting is van de vereniging uit 1828 is niet helemaal duidelijk. Deze thesis zet de belangrijkste (de directe) bronnen op een rij. Welke regels golden er voor de leden? Wat stond er op het programma? Wat kan er verder nog onderzocht worden