Geometry of quantum dynamics

Contribution List

3. Quantum Frequential Computing: a quadratic run time advantage for all algorithms

Mischa Woods

8/28/24, 9:45 AM

Quantum control is the research field focused on designing control fields that manipulate quantum systems. In traditional approaches, these control fields are treated classically. Quantum computers are a notable example where quantum control is employed to implement quantum logic gates. In this work, we explore quantum-quantum control, where both the system to be controlled and the controlling...

4. Maximal steady-state entanglement in autonomous quantum thermal machines

Shishir Khandelwal

8/28/24, 10:45 AM

It is well-known that failure to isolate a quantum system leads to its decoherence. However, quantum thermal machines offer an interesting perspective on this common wisdom. These are systems that explicitly use spontaneous interactions with the environment to perform a task. For these quantum systems, the environment is not detrimental but a resource. A basic conceptual question is therefore...

5. Quantum temporal correlation and tensors

Leonardo Silva Vieira Santos

8/28/24, 11:15 AM

In this talk I will discuss some results and some challenges involving temporal correlations in scenarios modeled by high-order quantum maps (tensors).

6. Reachability and Observability in Quantum Systems Theory: Aspects of a Unified Lie Frame

Thomas Schulte-Herbrüggen

8/28/24, 2:00 PM

Among the questions arising in quantum engineering there is a pair of practical yet fundamental ones: for a controlled quantum dynamical system, (1) what is the reachable set of sates given an initial condition?(2) For which observables (or more generally POVMs) can measurements give full information for system identification? In finite-dimensional closed systems, a unified (Lie) frame of...

7. State reachability in isolated systems

Konrad Szymański

8/28/24, 3:00 PM

8. Partial tomography of fermionic quantum simulators

Ahana Ghoshal

8/28/24, 3:30 PM

9. Newton's laws of motion can generate gravity-mediated entanglement

Marta Maria Marchese

8/28/24, 4:15 PM

10. SDP bounds on uncertainty relations and quantum codes

Felix Huber

8/29/24, 9:30 AM

I will introduce the framework of state polynomial optimization, a variant of the NPA hierarchy. It can be used to construct complete SDP hierarchies for quantum uncertainty relations and bounding the parameters of quantum codes. In both cases the Lovász theta number from graph theory plays a key role, and there are a range of relaxations available to make these SDPs numerically useful.

11. Rotational covariance restricts available quantum states

Fynn Otto

8/29/24, 10:30 AM

12. Nonclassicality, Entanglement and Positive Polynomials

Ties-Albrecht Ohst

8/29/24, 11:00 AM

Understanding quantum phenomena which go beyond classical concepts is a focus of modern quantum physics. Here, we show how the theory of nonnegative polynomials emerging around Hilbert's 17th problem, can be used to optimally exploit data capturing the nonclassical nature of light. Specifically, we show that nonnegative polynomials can reveal nonclassicality in data even when it is hidden from...

13. Quantum speed limit for perturbed open systems

Benjamin Yadin

8/29/24, 11:45 AM

Quantum speed limits provide upper bounds on the rate with which a quantum system can move away from its initial state. Here, we provide a different kind of speed limit, describing the divergence of a perturbed open system from its unperturbed trajectory. In the case of weak coupling, we show that the divergence speed is bounded by the quantum Fisher information under a perturbing Hamiltonian,...

14. Geometry and dynamics of non-Hermitian Hamiltonians

Ismaël Septembre

8/29/24, 12:15 PM

In this talk, I will present our latest results in the study of geometrical properties of non-Hermitian Hamiltonians and their link to unprecedented dynamics.

15. Spin squeezing and many-body entanglement estimation

Giuseppe Vitigliano

8/29/24, 2:30 PM

16. Estimation of entanglement monotones in permutationally invariant spin systems

Julia Mathe

8/29/24, 3:30 PM

We are interested in finding optimal entanglement witnesses and thereby bound entanglement monotones for interacting many-body systems that can be connected to experimentally relevant collective observables. For spin observables corresponding to two-body correlators, generalized spin squeezing inequalities [1, 2] are generally considered optimal witnesses. To begin with, we study thermal...

17. Metrological usefulness of entanglement and nonlinear Hamiltonians

Satoya Imai

8/29/24, 4:00 PM

A central task in quantum metrology is to exploit quantum correlations to outperform classical sensitivity limits. Metrologically useful entanglement is identified when the quantum Fisher information (QFI) exceeds a separability bound for a given parameter-encoding Hamiltonian. However, so far, only results for linear Hamiltonians are well-established. Here, we characterize metrologically...

18. Thermalization via scattering events

Michael Gaida

8/29/24, 4:45 PM

The equilibration of physical systems in contact to a thermal environment is one of the core assumptions of thermodynamics and has a variety of useful physical implications. While consequences of thermalization can be observed frequently in our everyday life, the dynamical processes behind this phenomenon have yet not been fully explored. In my talk i will consider the internal degrees of...

19. Non-equilibrium dynamics, disorder and entanglement

Henrik Wilming

8/30/24, 9:00 AM

I aim to first discuss results on the relation between entanglement in energy eigenstates and the presence or absence of thermalisation in many-body systems and relate these to recent results showing the presence of reviving product states in the disordered Heisenberg chain based on tensor network methods.

20. Magic states in the Asymmetric Quantum Rabi Model

Ernesto Benítez Rodríguez

8/30/24, 10:00 AM

The asymmetric quantum Rabi model (AQRM) is a modified version of the paradigmatic quantum Rabi model, which describes the interaction between a two-level system (qubit) and a quantum harmonic oscillator, typically a single mode of radiation field. The interplay of these degrees of freedom and its feasible experimental realizations in the context of quantum information setups make the AQRM a...

21. Quantum features from classical entropies

Tobi Haas

8/30/24, 10:30 AM

The scaling of local quantum entropies is of utmost interest for characterizing quantum fields, many-body systems and gravity. Despite their importance, being nonlinear functionals of the underlying quantum state often hinders their theoretical as well as experimental accessibility. Here, we show that suitably chosen classical entropies of standard measurement distributions capture the very...

22. Quantum Control of Radical-Pair Dynamics beyond Time-Local Optimization

Farhan Tanvir Chowdhury

8/30/24, 11:00 AM

We realize arbitrary-wave-form-based control of spin-selective recombination reactions of radical pairs in the low-magnetic-field regime. To this end, we extend the gradient-ascent pulse engineering (GRAPE) paradigm to allow for optimizing reaction yields. This overcomes drawbacks of previously suggested time-local optimization approaches for the reaction control of radical pairs, which were...