Dipolar interactions are ubiquitous in nature and rule the behavior of a

broad range of systems spanning from energy transfer in biological systems to

quantum magnetism. Here, we study magnetization-conserving dipolar induced

spin-exchange dynamics in dense arrays of fermionic erbium atoms confined in a

deep three-dimensional lattice. Harnessing the special atomic properties of

erbium, we demonstrate control over the spin dynamics by tuning the dipole

orientation and changing the initial spin state within the large 20 spin

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Single quantum light-emitters are valuable resources for engineered quantum

systems. They can function as robust single-photon generators, allow optical

control of single spins, provide readout capabilities for atomic-scale sensors,

and provide interfaces between stationary and flying qubits. Environmental

factors can lead to single emitters exhibiting "blinking", whereby the

fluorescence level switches between on and off states. Detailed

characterisation of this blinking behaviour including determining the switching

Vector vortex beam simultaneously carrying spin and orbital angular momentum

of light promises additional degrees of freedom for modern optics and emerging

resources for both classical and quantum information technologies. The

inherently infinite dimensions can be exploited to enhance data capacity for

sustaining the unprecedented growth in big data and internet traffic, and can

be encoded to build quantum computing machines in high-dimensional Hilbert

Entangled states with a positive partial transpose (so-called PPT states) are

central to many interesting problems in quantum theory. On one hand, they are

considered to be weakly entangled, since no pure state entanglement can be

distilled from them. On the other hand, it has been shown recently that some of

these PPT states exhibit genuinely high-dimensional entanglement, i.e. they

have a high Schmidt number. Here we investigate $d\times d$ dimensional PPT

states for $d\ge 4$ discussed recently by Sindici and Piani, and by

Correlations lie at the heart of almost all scientific predictions. It is

therefore of interest to ask whether there exist general limitations to the

amount of correlations that can be created at a finite amount of invested

energy. Within quantum thermodynamics such limitations can be derived from

first principles. In particular, it can be shown that establishing correlations

between initially uncorrelated systems in a thermal background has an energetic

In the problem of entanglement there exist two different notions. One is the

entanglement of a quantum state, characterizing the state structure. The other

is entanglement production by quantum operators, describing the action of

operators in the given Hilbert space. Entanglement production by statistical

operators, or density operators, is an important notion arising in quantum

measurements and quantum information processing. The operational meaning of the

We investigate whether entanglement can survive the thermalization of

subsystems. We present two equivalent formulations of this problem: 1. Can two

isolated agents, accessing only pre-shared randomness, locally thermalize

arbitrary input states while maintaining some entanglement? 2. Can

thermalization with local heat baths, which may be classically correlated but

do not exchange information, locally thermalize arbitrary input states while

maintaining some entanglement? We answer these questions in the positive at

Relational quantum queries are sometimes capable to effectively decide

between collections of mutually exclusive elementary cases without completely

resolving and determining those individual instances. Thereby the set of

mutually exclusive elementary cases is effectively partitioned into equivalence

classes pertinent to the respective query. In the second part of the paper, we

review recent progress in theoretical certifications (relative to the

assumptions made) of quantum value indeterminacy as a means to build quantum

We consider a general model, describing a quantum impurity with degenerate

energy levels, interacting with a gas of itinerant electrons, derive the

scaling equation and analyse the connection between its explicit form and the

symmetry of interaction. On the basis of this analysis we write down explicitly

the scaling equation for the interaction acting on $su(3)$ Lie algebra and

having either $SU(2)\times U(1)$, or $SU(2)$ symmetry.

We explore the electroluminescence efficiency for a quantum mechanical model

of a large number of molecular emitters embedded in an optical microcavity. We

characterize the circumstances under which a microcavity enhances harvesting of

triplet excitons via reverse intersystem-crossing (R-ISC) into singlet

populations that can emit light. For that end, we develop a time-local master

equation in a variationally optimized frame which allows for the exploration of