multimode_expts_tprocv2

multimode but v2

Handling Prepulses

Prepulses allow users to apply additional pulses before the main experiment pulse. These can be specified in the cfg.expt dictionary under the prepulse key. The structure for defining prepulses is as follows:

prepulse = {
    "pulse_name": {
        "chan": <channel>,
        "freq": <frequency>,
        "gain": <gain>,
        "phase": <phase>,
        "length": <length>,
        "type": <pulse_type>,
        "sigma": <sigma>,  # Optional, for Gaussian pulses
        "ramp_sigma": <ramp_sigma>  # Optional, for ramped pulses
    },
    ...
}

Notes:

• If the pulse_name corresponds to a predefined pulse (e.g., "pi_qubit_ge"), the system will use the default configuration from the hardware setup unless overridden.
• To modify specific parameters (e.g., phase), include the parameter in the prepulse dictionary.
• Ensure all required fields (chan, freq, gain, phase, length, type) are specified for custom pulses.

Sweeping Parameters

Sweeping parameters in experiments can be defined using the self.params dictionary. The structure is:

self.params[param_name] = {
    "label": <label>,
    "param": <parameter_to_sweep>,
    "param_type": <"pulse" or "time">
}

Definitions:

• label: A descriptive name for the parameter being swept (e.g., "pulse frequency").
• param: The specific parameter to sweep (e.g., "freq", "gain", "length").
• param_type: Indicates whether the parameter is associated with a pulse ("pulse") or a timing variable ("time").

Example:

To sweep the frequency of a pulse:

self.params["freq_sweep"] = {
    "label": "Pulse Frequency",
    "param": "freq",
    "param_type": "pulse"
}

Label Requirements for Sweeping Parameters

When defining sweeping parameters in the self.params dictionary, the label field must match one of the following:

1. Pulse Name Tag:

   • If the parameter being swept is associated with a pulse (e.g., frequency, gain, length), the label must match the name tag of the pulse as defined in the make_pulse method.
   • Example:

     self.params["freq_sweep"] = {
         "label": "main_pulse",  # Matches the pulse name tag
         "param": "freq",
         "param_type": "pulse"
     }

2. Delay Auto Tag:

   • If the parameter being swept is a timing variable, the label must match the tag used in the delay_auto method.
   • Example:

     self.params["time_sweep"] = {
         "label": "wait_prepulse",  # Matches the delay_auto tag
         "param": "time",
         "param_type": "time"
     }

Additional Details on Prepulses

The initialize_waveforms method in MMProgram handles the creation of both base pulses and prepulses. Here’s how prepulses are processed:

1. Base Pulses:

   • Predefined pulses like pi_qubit_ge are initialized with default parameters from the hardware configuration.

2. Custom Prepulses:

   • If prepulse is specified in cfg.expt, it should be a dictionary where each key is the name of the prepulse, and the value is another dictionary containing the pulse parameters.
   • Supported parameters for each prepulse:
     • freq: Frequency of the pulse.
     • chan: Channel on which the pulse is applied.
     • sigma: Standard deviation for Gaussian pulses.
     • length: Length of the pulse.
     • gain: Amplitude of the pulse.
     • type: Type of the pulse ("gauss", "flat_top", etc.).
     • n_sigmas: (Optional) Number of sigmas for Gaussian pulses (default: 4).
     • ramp_sigma: (Optional) Ramp sigma for flat-top pulses (default: 0.02).

3. Initialization Process:

   • Prepulses are added to the pulses_to_load dictionary.
   • If a prepulse name already exists in the base pulses, it is skipped to avoid overwriting.
   • The make_pulse method is called for each pulse, creating the waveform for later use.

Example Configuration for Prepulses

prepulse = {
    "custom_pulse": {
        "freq": 5.0e9,
        "chan": 1,
        "sigma": 0.1,
        "length": 0.4,
        "gain": 0.8,
        "type": "gauss",
        "n_sigmas": 6,
        "ramp_sigma": 0.03
    },
    "pi_qubit_ge": {}  # Uses default parameters
}

Notes:

• Ensure all required fields are specified for custom pulses.
• Default parameters are used for predefined pulses unless overridden.