Pulse sequence

Pulse shaping

In theory, a neutral atom-based quantum device is able to function both in a digital setting — working with quantum logic gates to implement any kind of quantum algorithm — and in an analog setting — interacting with all the atomic register to transmit energy to all the qubits in the system. Pulser Studio implements the latter, analog quantum computing paradigms, wherein we are interacting with the atomic register via specifically designed laser pulses.

Therefore the next big step with an implementation is the so-called pulse shaping, transforming the (mathematical) problem at hand into a language understandable by a neutral atom device. This translation is typically a two-step process:

1. First the problem we investigate gets reformulated so that the aforementioned energy, a so-called Hamiltonian appears.

Note

The word “Hamiltonian” can be scary if you are a quantum novice. Think about this concept as a physical black box describing the targeted interaction between atoms of the register we are working with.

2. After this, the obtained construct has to be transformed into a series of laser signals, this passage can be more or less straightforward based on the complexity of the problem.

Pulse sequence

Visual representation of the pulse sequence.

In Pulser Studio, pulses are managed on the Channels panel. It offers a timeline view of the sequence of pulses, as they will be executed by the device, and a visualization of the main characteristics of each pulse, such as waveform, amplitude, phase and detuning.

Depending on the target device, a sequence can include multiple channels.

Pulses can easily be created, duplicated or removed by right-clicking the timeline graph, and moved by drag-and-drop.

When creating a new pulse, default values will be assigned, that you can fine-tune in the Pulse panel of the right sidebar, until you get the pulse necessary for your problem.

The Pulse panel, allowing fine-grained control over all characteristics of a single pulse.

Note for advanced users

• Pulser and hence Pulser Studio provides a low-level access to shaping the laser signal, just as an optics engineer would do, allowing a total control over the waveshape, its amplitude (the Rabi frequency), phase (relative between qubit and field frequency) as well as the detuning (difference between qubit resonance and field frequency). Some of these parameters can be directly extracted from the source (spin) and 1-body interaction terms.
• It is important to note that not all Hamiltonians can be encoded. For the Ising or XY(Z) spin type Hamiltonians, the encoding comes more naturally, however the range of accessible Hamiltonians can be extended by some engineering techniques.