Month: October 2021

Configuring Emacs, the cool way

A super cool method to set the configuration of emacs, following DistroTube

Emacs requires tweaking the init.el file in the .emacs.d dir in home

init.el is written in emacs-lisp and a bit obscure to understand

One can use the wonderful emacs org-mode to code the init.el by using an auxiliary config.org placed in any directory

The steps are described below (generated by emacs org-mode)

In addition to set a proper configuration, it also useful to use emacs as a client, which speeds up running emacs.

This is done, first running the emacs daemon

/usr/bin/emacs --daemon

And then any time we launch emacs we use

emacsclient -c -a 'emacs'

In Linux systems, the emacs daemon can be launched at startup by adding the service to the systemd as detailed here

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1. How to configure emacs by a emacsconfig.org file
- 1.1. Set your init.el in .emacs.d
- 1.2. Write emacsconfig.org

1 How to configure emacs by a emacsconfig.org file

1.1 Set your init.el in .emacs.d

Write the following init.el in .emacs.d

(org-babel-load-file
 (expand-file-name
  "~/org/emacsconfig.org"
 user-emacs-directory))

Here emacsconfig.org is the org configuration file with its path You can set any file

In this file we have various functions

Org Babel

Org Babel is a wonderful tool to use different languages in a single org file

org-babel-load-file

Loads Emacs Lisp source blocks in the org file

expand-file-name

Replace the file name with absolute path

user-emacs-directory

Is the directory where the Emacs-specific files are placed .emacs.d typically, where the search of the file starts

1.2 Write emacsconfig.org

In the .org file for the configuration we will write different parts as pieces of emacs lisp code. For example

* FRAME SIZE
#+begin_src emacs-lisp
(add-to-list 'default-frame-alist '(width . 180))
(add-to-list 'default-frame-alist '(height . 90))
#+end_src

* FONTSIZE
#+begin_src emacs-lisp
(set-face-attribute 'default (selected-frame) :height 150)
#+end_src

Boson sampling solitons by quantum machine learning

https://arxiv.org/abs/2110.12379

We use a neural network variational ansatz to compute Gaussian quantum discrete solitons in an array of waveguides described by the quantum discrete nonlinear Schroedinger equation. By training the quantum machine learning model in the phase space, we find different quantum soliton solutions varying the number of particles and interaction strength. The use of Gaussian states enables measuring the degree of entanglement and the boson sampling patterns. We compute the probability of generating different particle pairs when varying the soliton features and unveil that bound states of discrete solitons emit correlated pairs of photons. These results may have a role in boson sampling experiments with nonlinear systems and in developing quantum processors to generate entangled many-photon nonlinear states.

Quantum machine learning and boson sampling

Training Gaussian boson sampling by quantum machine learning

published in Quantum Machine Intelligence 3, 26 (2021)

We use neural networks to represent the characteristic function of many-body Gaussian states in the quantum phase space. By a pullback mechanism, we model transformations due to unitary operators as linear layers that can be cascaded to simulate complex multi-particle processes. We use the layered neural networks for non-classical light propagation in random interferometers, and compute boson pattern probabilities by automatic differentiation. This is a viable strategy for training Gaussian boson sampling. We demonstrate that multi-particle events in Gaussian boson sampling can be optimized by a proper design and training of the neural network weights. The results are potentially useful to the creation of new sources and complex circuits for quantum technologies.