Release 0.7.0

What's Changed

BREAKING

• Removed Qx.Remote, Qx.Remote.Config, and Qx.RemoteError. The qx_server-based hardware path has been replaced by direct-to-IBM execution via Qx.Hardware. There is no shim; the credential shape and call sites are different.

  Migration:

  # before (0.6.x)
  config = Qx.Remote.Config.new!(url: "...", api_key: "...")
  {:ok, result} = Qx.Remote.run(circuit, config, backend: "ibm_brisbane", shots: 4096)
  
  # after (0.7.x)
  config =
    Qx.Hardware.Config.new!(
      portal_url: "https://api.qxquantum.com",
      portal_token: "<qxportal token>",
      ibm_api_key: "<ibm cloud api key>",
      ibm_crn: "<ibm quantum service crn>",
      ibm_region: "us-east",
      backend: "ibm_brisbane",
      shots: 4096
    )
  
  {:ok, result} = Qx.Hardware.run(circuit, config)

  The new Qx.Hardware.Config.from_env!/1 reads QX_PORTAL_URL, QX_PORTAL_TOKEN, QX_IBM_API_KEY, QX_IBM_CRN, QX_IBM_REGION, QX_IBM_BACKEND for a one-liner setup.

Added

• Qx.Hardware — public namespace owning the full direct-to-IBM execution pipeline (IAM exchange → qxportal transpile → IBM submit → poll → result-build).
• Qx.Hardware.Config — credential + execution-preference struct (portal_url, portal_token, ibm_api_key, ibm_crn, ibm_region, backend, optimization_level, shots). Validates region against the IBM allowlist, optimization_level 0..3, shots 1..100_000, portal URL scheme.
• Qx.Hardware.Ibm — Req-based client for IBM Quantum (Qiskit Runtime REST API). IAM exchange + 401-refresh-retry, backends list, backend configuration, Sampler V2 submission, poll loop with Pascal-Case status allowlist, sample-aggregation to counts, best-effort cancel.
• Qx.Hardware.Portal — Req-based client for the qxportal /api/v1/me and /api/v1/transpile endpoints. Atomize allowlist for response keys.
• Qx.Hardware.NoMeasurementsError — raised when a circuit submitted to hardware has no measure/2 instructions.
• Qx.Hardware.ConfigError — typed validation error for Qx.Hardware.Config.
• Privacy invariant — two independent HTTP clients; the portal token never reaches IBM, and the IBM API key/CRN never reach the portal.
• Status callback — pipeline progress events ({:portal, :transpiling}, {:ibm, :polling, status}, …). All atoms literal (Iron Law #1 — no String.to_atom on caller input).

Removed

• Qx.Remote, Qx.Remote.Config, Qx.RemoteError (see BREAKING above).
• examples/remote/ — superseded by examples/hardware/run_on_ibm.exs.

Dependencies

• New test-only dep: {:bypass, "~> 2.1"} (HTTP stubbing for portal + IBM tests).
• Explicit pin: {:jason, "~> 1.4"} (previously transitive via Req/Plug).

Installation

Add to your mix.exs:

def deps do
  [
    {:qx_sim, "~> 0.7.0"}
  ]
end

Documentation

• Hex.pm: https://hex.pm/packages/qx_sim/0.7.0
• Docs: https://hexdocs.pm/qx_sim/0.7.0