Stay up to date with the latest Boulder Opal release notes

Boulder Opal 23.0.0

September 14, 2023

Major changes

  • The gradient graph node has been removed.

Boulder Opal 22.2.0

August 22, 2023

New features

  • We've improved the search experience in the documentation.

Boulder Opal 22.1.0

July 24, 2023

New features

Boulder Opal 22.0.3

July 18, 2023


  • The graph.reverse operation, which reverses a tensor along specified dimensions, now accepts a scalar for axes. See reference documentation for more information.

Boulder Opal 22.0.2

June 5, 2023

Bug fixes

  • We've fixed an issue that prevented the reference documentation from loading when the cookies are large.

Boulder Opal 22.0.1

May 23, 2023


  • New base image for Nginx that supports larger cookies (and prevents 400 error) (#756)

Boulder Opal 22.0.0

March 30, 2023

Breaking changes

  • We've removed support for Python 3.7.

Boulder Opal 21.0.1

March 20, 2023

New features

  • We've added the function plot_density_matrix to the Q-CTRL Visualizer to create a heatmap with the absolute values of a density matrix’s elements. You can learn more about it in its reference page.
  • We've added a user guide on automating complex calibration tasks using the Q-CTRL Experiment Scheduler.

Bug fixes

  • We've fixed an issue when trying to request a task with REVOKED status.

Boulder Opal 21.0.0

March 1, 2023

Breaking changes

  • We've added enforcement for users in multiple organizations to specify the computing environment by passing an organization slug when instantiating a Qctrl object.
  • We've changed the default value of optimization_count in calculate_optimization and calculate_stochastic_optimization to 4. This updated value is sufficient for a wide range of optimization problems. However, depending on the optimization landscape, a larger value will help in finding lower costs at the expense of prolonging computation time.

New features

  • We’re excited to announce the Boulder Opal basic plan as a free version to make it widely accessible to researchers, students and engineers in the quantum community. The Boulder Opal basic plan is powered by our enhanced cloud infrastructure (beta phase of development) that provides a dedicated computing environment to deliver a better user experience and accelerated computation.
  • We've added a new node to calculate the steady state of a time-independent open quantum system. You can learn out more it in the reference documentation and in this user guide.
  • We've added the function plot_population_distributions to the Q-CTRL Visualizer to create a bar graph of the population distribution for a state. You can learn more about it in its reference page.
  • We've deprecated the plot_populations function in the Q-CTRL Visualizer, and it will be removed in the future. Please use plot_population_dynamics instead.

Boulder Opal 20.2.0

February 20, 2023

New features

  • We've added the functionality to cancel in-progress calculations. Now, when you cancel a calculation with Queued or Running status, for example, using a keyboard interrupt or interrupting a notebook kernel, the corresponding calculation on the server is also stopped.
  • We've added the functionality to cancel calculations with Queued status in activity monitor on Boulder Opal web app.