Quantum Computing Architecture Diagram

Quantum Computing Architecture Design: An complete explanation of every layer

Layers of quantum computers are stacked systems with different functions in running quantum calculations. From developing a quantum algorithm to getting a final result, knowing these levels enables us to better appreciate how quantum computers handle information.

Every layer uses interactions with the one below it to effectively do quantum calculations. A flowchart showing how these levels interact is below.

Layer 1: Application Layer (User Interface)

Written and carried out quantum programs are housed in this uppermost layer, sometimes known as Quantum Software and Algorithm Layer. Though it is not exactly part of the quantum computer itself, this layer serves as the user interface, the conceptual operating system (should one exist in the future), and the coding environments enabling users to create and engage with quantum algorithms. Hardware-independent, this layer emphasises the problem to be solved above the details of the underlying quantum hardware. Experts from several disciplines, like finance, materials science, or cryptography, work with quantum algorithm inventors here to find issues that would profit from quantum computation and communicate them in an appropriate way. Usually, this layer produces a high-level overview of the quantum method to be carried out. For database searching or integer factorising, for example, a researcher would wish to apply Grover’s or Shor’s algorithms. The tools and abstractions offered by the application layer enable one to communicate these algorithms without resorting to the complexities of qubit control or hardware restrictions. Particularly for uses requiring manipulation of a vast amount of data items to get a statistical conclusion, quantum computing promises to become a computational game changer permitting the implementation of many algorithms far quicker than their conventional equivalents. Physical system simulation, cryptography, and machine learning are among the possibly interesting fields.

Here, what happens?
Users create quantum programs in quantum programming languages such Q# (Microsoft), PennyLane (Xanadu), Qiskit (IBM), Cirq (Google).

• The code covers quantum operations including: quantum machine learning (for artificial intelligence applications), Grover’s Algorithm (for rapid searching), Shor’s Algorithm (for factorisation).
• Example:- A scientist uses a quantum algorithm developed in Qiskit to replicate a molecule for pharmaceutical development.

The programme is next forwarded to the Classical Control Processor for compilation.

Layer 2: Classical Control Layer: (Compiling & Optimization)

This layer converts high-level quantum code into machine-executable quantum instructions.
This layer acts as the vital link between the physical quantum hardware and the abstract quantum algorithm. It is responsible for several key functions:

• Quantum Algorithm Compilation and Optimization: High-level quantum algorithms must be converted into a series of low-level instructions that the quantum hardware can follow. Compilation is the process by which the abstract algorithm is transformed into a tangible collection of quantum gates that can be used with particular qubits. Furthermore, this layer generally incorporates optimization processes to reduce the number of gates, minimize execution time, and translate the algorithm efficiently onto the available qubit connectivity of the quantum processor. This improvement is significant since present quantum technology has constraints in terms of the amount of qubits and their connection. The goal of quantum software architecture is to enable architects to model, develop, and evolve quantum computing software at higher abstraction levels by utilising architecture-centric procedures, practices, and description languages.
• Making instructions: Once the sequence of compiled and optimised quantum gates is ready, it needs to be turned into the specific control signals that the underlying physical qubits need to put these gates into action. For example, microwave pulses are needed for superconducting qubits, and laser pulses are needed for trapped ions. To do this, you need to think about the exact factors and features of the target quantum hardware.
• State Preparation and Measurement Control: The classical control layer is also accountable for preparing the initial state of the qubits, which is generally the level 0 state, prior to the commencement of the quantum computing. After the execution of the quantum algorithm, this layer initiates the measurement process to read out the final state of the qubits. The measurement results are classical bits that are then passed back to the classical processing part of this layer for further analysis and interpretation.
• 
  Quantum Instruction Set Architecture (QISA): This layer operates based on a Quantum Instruction Set Architecture (QISA), which defines the low-level instructions that the quantum hardware can understand and execute. cQASM (common Quantum Assembly Language) and eQASM (executable Quantum Assembly Language) are two examples of these kinds of systems. The compiler in this layer translates the quantum program into these QISA instructions.

What Occurs in This Scene?

• Quantum instructions are generated following the compilation of the quantum program.
• Optimisations are carried out in regard to:
  o Reduce errors
  o Minimize gate operations
  o Accelerate the rate of execution
• Quantum error correction codes are applied to prevent computation failures.

Example: The quantum compiler translates a Qiskit program into quantum assembly language (cQASM).
After then, the code that has been optimised is transmitted to the Quantum Control System.

In the Next step, the quantum instructions that have been built are sent to the Quantum Control System in order to produce control signals.

 Layer 3: Quantum Control System Layer (Signal Processing)

This layer is responsible for sending physical signals to control qubits.

Digital Layer (Interface Layer):

Along with the Classical Control Layer, the Analog/Physical Layer acts as a bridge between them. It takes the micro-instructions from the control layer, which are basically digital descriptions of the quantum operations that need to be done, and turns them into the exact digital signals that the analog control systems below will use to run. On the other hand, it could take the analog measurement signals from the Quantum Hardware Layer and turn them into a digital format that the Classical Control Layer can use. This layer bridges the gap between the digital logic of the control system and the analog nature of the physical quantum hardware. It deals with the precise timing and sequencing of control pulses required to manipulate the qubits accurately.

Analog layer:

producing voltage signals with particular phase and amplitude modulations that are necessary to carry out operations on the qubits is the responsibility of the analog layer in a quantum computing architecture. This layer is responsible for producing the voltage signals. These signals, which are similar to waves, are sent to the quantum layer below in order to carry out the qubit operations that must be performed.

An explanation of how the analog layer operates, broken down according to the sources, is as follows:

• In accordance with the digital descriptions that are supplied by the digital layer, it induces the generation of analog pulses. The digital layer is responsible for interpreting these digital descriptions, which are in the form of microinstructions, and converting them into the required signals for the analog layer.
• These analog signals contain phase and amplitude modulations, which are essential for changing the state of the qubits in the quantum layer.
• The analog layer, together with the digital and quantum processing layers, is incorporated into the same chip and is a component of the Quantum Processing Unit (QPU). The quantum processing unit (QPU) and the classical layer together make up the whole of the quantum computer.
• As is the case with the digital layer, the analog layer functions at ambient temperature whenever it is active.

What happened in this Layer?

• These signals are responsible for controlling qubits and carrying out quantum gate operations.
• The quantum instructions that are received from the classical processor are transformed into microwave or laser pulses.
• A variety of control systems include:
  • Pulses of microwaves (Superconducting qubits, which are used by IBM and Google)
  • Laser pulses (trapped-ion qubits, offered by Honeywell and known as IonQ)
• Magnetic fields, sometimes known as spin qubits, are used in silicon quantum computing by Intel.

Example:

• The application of a microwave pulse to a superconducting qubit results in the qubit being flipped from the state of 0 to the state of 1.
• An additional pulse is responsible for carrying out an entanglement operation between two qubits.

Next Step, the signals will cause the quantum gates in the Quantum Processing Unit (QPU) to become active.

 Layer 4: Quantum Processing Unit (QPU) Layer (Core Computing)

In this part of the quantum computer, qubits and quantum gates are responsible for carrying out the computations that are really being performed.

Exactly What Occurs Within This Layer?

• Information that is quantum can be stored and processed using qubits.
• Quantum gates are responsible for performing computations by manipulating qubits.
• In order to do sophisticated calculations, entanglement and superposition are utilized.
• In the short term, quantum registers are used to store quantum data.

Components of the QPU:

Example:-

• The quantum circuit uses Grover’s algorithm to search a database.
• In order to discover the correct answer more quickly than a classical computer, qubits go through the processes of superposition, entanglement, and interference.

The next step involves stabilizing the findings and measuring them in the Physical Layer in the next step.

 Layer 5: Physical Layer (Cooling & Stability)

In addition to being known as the Hardware and Error Correction Layer, this layer is responsible for ensuring that qubits are stable and safeguarded against faults.

Exactly What Occurs Within This Layer?

Cryogenic cooling is a technique that maintains qubits at extremely low temperatures, around 15 millikelvin for superconducting qubits.

• Detecting and correcting quantum defects is the responsibility of error correction techniques, such as Surface Codes.
• In order to avoid decoherence, the stability of the qubit is not compromised.

Example:-

• In order to get qubits down to temperatures near to absolute zero (-273 degrees Celsius), IBM’s quantum computers make use of dilution refrigerators.
• Error correction methods repair qubit flaws in order to enhance the dependability of the system.

In the last step, the results of the quantum computation are measured and then transmitted back to the conventional computational system.

Table of All Layers in Quantum Computer Architecture