Add quilt.rst and some information on where to find quilt spec

docs/source/index.rst

@@ -88,9 +88,9 @@ Contents
 
 .. toctree::
    :maxdepth: 3
-   :caption: Quilt
+   :caption: Quil-T
 
-   quilt_proposal
+   quilt
    quilt_getting_started
    quilt_waveforms
    quilt_parametric

docs/source/quilt.rst

@@ -0,0 +1,34 @@
+.. _quilt:
+
+Quil-T
+======
+
+Quil-T is an extension to Quil which introduces pulse-level control to
+quantum programs. With Quil-T one can describe a program at a level
+lower than is typically permitted in circuit-type programs, with
+explicit control over the RF waveforms played by the QPU's control
+hardware. In particular this imbues programs with a notion of *time*,
+hence the `T` suffix.
+
+The Quil compiler `quilc` was developed to support most users in their
+pursuit for producing an optimal program from a high-level
+language. In contrast Quil-T was developed to enable the low-level and
+precise control desired by power-users. For example, for many users
+the implementation details of a Hadamard gate are not particularly
+important, and indeed the behind-the-scenes realisation of a Hadamard
+gate are likely to change over time as gate implementations are
+recalibrated to provide the best results. If you instead you are
+interested in those details, and in particular you want to control
+those details, then pulse-level control with Quil-T is the way to
+go. With Quil-T you can define precisely what you mean by `H 0`, you
+can perform experiments to characterize the underlying hardware such
+as determining `T1`. The hardware is almost at your fingertips.
+
+.. note::
+
+   Quil-T is not yet finalized and subject to change. The following
+   link should be updated upon the release of Quil-T.
+
+For examples, see the adjacent notebooks. For more information, see
+the Quil-T proposal at the `Quil project homepage
+<https://github.com/rigetti/quil/tree/bugfix/quilt-rfc-improvements/rfcs/analog>`_.