doc: Add documentation for DRAG

doc/source/protocols/drag/drag.rst

@@ -0,0 +1,94 @@
+DRAG experiments
+================
+
+In this section we show how to run Ramsey experiments using Qibocal
+
+.. _drag:
+
+
+DRAG :cite:p:`Motzoi_2009, Gambetta_2011`: pulses can be used to lower both phase and leakage errors,
+it consists in adding a quadrature component to the pulse which is proportional
+to the time derivative of the phase component. Given a pulse with a phase component :math:`\Omega_x`
+the quadrature component :math:`\Omega_y` is evaluated as
+
+.. math::
+
+    \Omega_y (t) = \beta \frac{d\Omega_x}{dt} ,
+
+where :math:`\beta` is a scaling parameter.
+
+Qibocal provides two separate protocols to extract :math:`\beta`.
+
+
+Method 1
+--------
+
+:math:`\beta` can be extracted by playing the pulse sequence composed by
+:math:`[R_X(\pi) - R_X(-\pi)]^N` for different values of :math:`\beta` as shown in  :cite:p:`Sheldon_2016`.
+The post-processing consists in measuring the probability of :math:`\ket{0}` for every :math:`\beta`
+and fitting the curve with a cosine. The correct :math:`\beta` value is the one which maximizes
+the curve.
+
+Parameters
+^^^^^^^^^^
+
+.. autoclass:: qibocal.protocols.drag.DragTuningParameters
+  :noindex:
+
+Example
+^^^^^^^
+
+.. code-block:: yaml
+
+      - id: drag tuning
+        operation: drag_tuning
+        parameters:
+            beta_start: -1
+            beta_end: 1
+            beta_step: 0.1
+            nflips: 5
+            unrolling: true
+
+
+Running this protocol you should get something like this:
+
+.. image:: drag_tuning.png
+
+
+Method 2
+--------
+
+The second method consists in playing two different sequences
+:math:`R_Y(\pi) R_X(\pi/2)` and :math:`R_X(\pi) R_Y(\pi/2)` which are two
+of the AllXY pulses which exhibit opposite sign of phase error as highlighted
+in :cite:p:`reed2013entanglementquantumerrorcorrection`.
+The post-processing consists in measuring the probability of :math:`\ket{1}` for every :math:`\beta`
+and performing a linear fit for both sequences. The correct :math:`\beta` value is the one where the two lines
+cross.
+
+Parameters
+^^^^^^^^^^
+
+.. autoclass:: qibocal.protocols.drag_simple.DragTuningSimpleParameters
+  :noindex:
+
+Example
+^^^^^^^
+
+.. code-block:: yaml
+
+      - id: drag simple
+        operation: drag_simple
+        parameters:
+            beta_start: -1
+            beta_end: 1
+            beta_step: 0.1
+            unrolling: true
+
+.. image:: drag_simple.png
+
+
+Requirements
+^^^^^^^^^^^^
+
+- :ref:`single-shot`

doc/source/protocols/index.rst

@@ -28,6 +28,7 @@ In this section we introduce the basics of all protocols supported by ``qibocal`
     dispersive_shift
     allxy
     flipping
+    drag/drag
     readout_mitigation_matrix
     readout_optimization
     standard_rb

doc/source/refs.bib

@@ -190,3 +190,53 @@ @article{Nielsen_2002
    author={Nielsen, Michael A},
    year={2002},
    month=oct, pages={249–252} }
+
+@article{Motzoi_2009,
+   title={Simple Pulses for Elimination of Leakage in Weakly Nonlinear Qubits},
+   volume={103},
+   ISSN={1079-7114},
+   url={http://dx.doi.org/10.1103/PhysRevLett.103.110501},
+   DOI={10.1103/physrevlett.103.110501},
+   number={11},
+   journal={Physical Review Letters},
+   publisher={American Physical Society (APS)},
+   author={Motzoi, F. and Gambetta, J. M. and Rebentrost, P. and Wilhelm, F. K.},
+   year={2009},
+   month=sep }
+
+
+@article{Gambetta_2011,
+   title={Analytic control methods for high-fidelity unitary operations in a weakly nonlinear oscillator},
+   volume={83},
+   ISSN={1094-1622},
+   url={http://dx.doi.org/10.1103/PhysRevA.83.012308},
+   DOI={10.1103/physreva.83.012308},
+   number={1},
+   journal={Physical Review A},
+   publisher={American Physical Society (APS)},
+   author={Gambetta, J. M. and Motzoi, F. and Merkel, S. T. and Wilhelm, F. K.},
+   year={2011},
+   month=jan }
+
+@article{Sheldon_2016,
+   title={Characterizing errors on qubit operations via iterative randomized benchmarking},
+   volume={93},
+   ISSN={2469-9934},
+   url={http://dx.doi.org/10.1103/PhysRevA.93.012301},
+   DOI={10.1103/physreva.93.012301},
+   number={1},
+   journal={Physical Review A},
+   publisher={American Physical Society (APS)},
+   author={Sheldon, Sarah and Bishop, Lev S. and Magesan, Easwar and Filipp, Stefan and Chow, Jerry M. and Gambetta, Jay M.},
+   year={2016},
+   month=jan }
+
+@misc{reed2013entanglementquantumerrorcorrection,
+      title={Entanglement and Quantum Error Correction with Superconducting Qubits},
+      author={Matthew Reed},
+      year={2013},
+      eprint={1311.6759},
+      archivePrefix={arXiv},
+      primaryClass={quant-ph},
+      url={https://arxiv.org/abs/1311.6759},
+}