This CECAM workshop will bring together leading members and tool developers from two main quantum transport communities: the one relying on the Non-equilibrium Green’s Functions (NEGF) [1] [2] and the other dealing with quantum phase-space [3] [4]. The aim will be to establish bridges between these two communities by presenting the latest achievements in both areas, with emphasis on the physical models, numerical techniques, and technology applications.
We believe that time has come for these approaches to be reunited in order to solve the multiscale challenges that the nonequilibrium quantum transport modelling of contemporary and future nano-devices is facing, especially when going beyond electron transport phenomena.

The main topics that will be discussed and addressed at this workshop are therefore the following:

- State-of-the-art in (semi-)empirical and ab initio NEGF;
- State-of-the-art in quantum phase-space methods (Boltzmann and Wigner);
- Novel applications beyond electron transport, e.g. thermal transport;
- Numerical methods and algorithms.

The meeting will inspire novel development ideas within each particular approach, while at the same time paving the way for fruitful collaborations. In effect, all quantum transport methods are confronted with similar challenges: (i) improving the accuracy of the physical models, (ii) increasing the size of the simulated domains, (iii) reducing the associated computational burden, (iv) going beyond electronic applications, and (v) moving from steady-state to transient investigations. In this context, we will examine how one community can benefit from the advances made by the other, thus laying the ground for more synergistic tool developments. Our key motivation is to demonstrate the complementarity modelling approaches between NEGF and phase-space and to find out how they can be combined, even integrated with each other, for example as part of the next-generation multi-functional, multi-scale transport simulators.

Hence, the CECAM workshop on “Quantum Transport Methods and Algorithms: From Particles to Waves Approaches” will answer the following questions:

- Can useful information be exchanged between a NEGF and Wigner solver (parameter coupling)?
- Can a wave function (NEGF) and particle (Wigner) representation of carriers cohabit within a single simulation domain (tight coupling)?
- Are there specific applications that are only accessible by one type of approaches and not by the other(s)? Could further developments fill eventual gaps?
- Can a common set of parallel numerical algorithms (eigenvalue, sparse linear, banded solver or stochastic) be identified?
- What are the next big innovations to come in quantum transport modelling?
The semiconductor industry is aggressively pushing tool suppliers for the delivery of advanced quantum transport packages that can compete with the classical drift-diffusion equations. This workshop will be the first step towards the assembly of novel device simulators that fulfil the industrial requirements and expectations.