Daily rc sync to master (#6200)

Automatic sync from the release candidate to master during a feature
freeze.

---------

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Co-authored-by: Christina Lee <christina@xanadu.ai>
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Co-authored-by: Guillermo Alonso-Linaje <65235481+KetpuntoG@users.noreply.github.com>
Co-authored-by: Mudit Pandey <mudit.pandey@xanadu.ai>
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doc/code/qml_spin.rst

@@ -0,0 +1,15 @@
+qml.spin
+=========
+
+Overview
+--------
+
+This module contains functions and classes for creating and manipulating Hamiltonians for the spin models.
+
+.. currentmodule:: pennylane.spin
+
+.. automodapi:: pennylane.spin
+ :no-heading:
+ :no-main-docstr:
+ :skip: Lattice
+ :include-all-objects:

doc/development/deprecations.rst

@@ -16,7 +16,7 @@ Pending deprecations
  - Will be removed in v0.39
 
 * The logic for internally switching a device for a different backpropagation
- compatible device is now deprecated, as it was in place for the deprecated `default.qubit.legacy`.
+ compatible device is now deprecated, as it was in place for the deprecated ``default.qubit.legacy``.
 
  - Deprecated in v0.38
  - Will be removed in v0.39 

doc/index.rst

@@ -216,7 +216,8 @@ PennyLane is **free** and **open source**, released under the Apache License, Ve
  code/qml_qaoa
  code/qml_qchem
  code/qml_qnn
-
+ code/qml_spin
+
 .. toctree::
  :maxdepth: 1
  :caption: Internals

doc/introduction/templates.rst

@@ -124,6 +124,45 @@ state preparation is typically used as the first operation.
 
 .. _intro_ref_temp_subroutines:
 
+Arithmetic templates
+--------------------
+
+Quantum arithmetic templates enable in-place and out-place modular operations such 
+as addition, multiplication and exponentiation.
+
+.. gallery-item::
+ :description: :doc:`PhaseAdder <../code/api/pennylane.PhaseAdder>`
+ :figure: _static/templates/arithmetic/phaseadder.png
+
+.. gallery-item::
+ :description: :doc:`Adder <../code/api/pennylane.Adder>`
+ :figure: _static/templates/arithmetic/adder.png
+
+.. gallery-item::
+ :description: :doc:`OutAdder <../code/api/pennylane.OutAdder>`
+ :figure: _static/templates/arithmetic/outadder.png
+
+.. gallery-item::
+ :description: :doc:`Multiplier <../code/api/pennylane.Multiplier>`
+ :figure: _static/templates/arithmetic/multiplier.png
+
+.. gallery-item::
+ :description: :doc:`OutMultiplier <../code/api/pennylane.OutMultiplier>`
+ :figure: _static/templates/arithmetic/outmultiplier.png
+
+.. gallery-item::
+ :description: :doc:`ModExp <../code/api/pennylane.ModExp>`
+ :figure: _static/templates/arithmetic/modexp.png
+
+.. gallery-item::
+ :description: :doc:`IntegerComparator <../code/api/pennylane.IntegerComparator>`
+ :figure: _static/templates/arithmetic/integercomparator.png
+
+
+.. raw:: html
+
+ <div style='clear:both'></div>
+
 Quantum Chemistry templates
 ---------------------------