The Quantum Internet is a hypothetical high-speed internet that provides ultra-secure connections to quantum devices around the world. In the future, the quantum internet will be a collection of networked mega-clusters composed of small quantum infrastructure separated by long distances or international borders.
While quantum computers exist in the physical world, the concept of a quantum internet remains theoretical for now. Existing quantum networks do not currently extend beyond research labs, but they are relevant for quantum computing. For example, the quantum Internet is based on quantum mechanical phenomena such as superposition and entanglement, and implements quantum cryptography protocols to ensure communication security.
Research teams are conducting experiments to establish long-distance entanglement, and scientists continue to theorize how they expect a quantum internet to work once developed. When fully realized, the quantum Internet will be combined with the classical Internet to solve complex problems and achieve secure communication and high-speed computing.
Classical Internet and Quantum Internet
The quantum internet will not replace the classical internet. Instead, it will add better capabilities to connect devices in homes, commercial businesses, and enterprises. Current quantum computers can access the classical Internet to perform certain tasks. All quantum devices will eventually need to support a quantum internet via quantum network protocols.
data unit
The classic Internet enables devices to transmit, receive, compute and store information represented in bits. A bit is the smallest unit in computing and represents the logical state of a device, such as on and off, represented as 0 or 1 respectively. A set of bits can represent a character in text, a pixel in an image, or a frame in a video. In other words, groups of bits represent every piece of information on the Internet.
The quantum internet enables interconnected quantum networks to exchange information, known as qubits, encoded in two quantum states. Similar to how a bit represents a 0 or a 1, a qubit represents two quantum states.
Quantum states describe the polarization of a photon or the spin of an electron. These properties enable qubits to encode information in quantum networks. They push the qubit into a superposition state, in which the qubit is in two states at once, and any change in the qubit affects both states.
In a quantum internet, logical operations such as error correction or encryption can change a single qubit without affecting other qubits in the packet. This differs from the deterministic processing used in the classic Internet, where transmissions vary based on the overall information in the packet.
Operation mode
The classic Internet sends data from source to destination at high speed. Each source and destination has a unique IP address. Network protocols encapsulate information in packets and send the data over a channel from the sender to the receiver. The classic Internet relied on the TCP/IP protocol to ensure reliable data transmission, IP addressing, routing, security, and other important network requirements.
Because a quantum internet is still hypothetical and in the early stages of small-scale development, a well-defined suite of network protocols like TCP/IP does not yet exist. However, researchers have developed various quantum network protocols over the years that make current quantum communications possible. Quantum network protocols rely on the principles of quantum mechanics to exchange qubits within the network.
Coverage
The classic Internet is a global interconnected network of smaller networks around the world. Billions of networks make up the Internet, and billions of users access it every day to browse the web, consume information, and communicate with others.
The reach of the quantum internet is difficult to measure because it only exists in hypothetical scenarios. Quantum researchers create entangled states over long distances to test the scaling of quantum networks. Research shows that quantum network range for fiber-optic based communications is approximately 62 miles. Scientists use quantum repeaters to capture weak signals for retransmission to increase the range of quantum communications.
Quantum vs. Classical Internet Security
In the classic Internet, network security protocols form secure channels to enable uninterrupted connections. Examples of cybersecurity protocols include:
- IP security.
- VPN tunneling protocol.
- Secure Sockets Layer (SSL).
- Secure Shell (SSH).
- Tunnel Layer Security (TLS).
- Wi-Fi Protected Access (WPA).
However, in a quantum internet, the development of cryptographic protocols relies on quantum key distribution (QKD). QKD shares an unreplicable secret key between devices connected to the quantum internet. Hackers cannot accurately determine the state of entangled qubits because any measurement would collapse the wave function. The quantum internet also implements quantum encryption protocols to protect communications.
reliability
The classic Internet generally operates reliably, but the reliability of packet transmission is not always guaranteed. Networks often experience packet loss due to factors such as congestion and hardware failures. Packet loss prevents data from being transmitted over the Internet and sometimes causes delays.
The quantum internet may also suffer from qubit loss, a problem similar to packet loss. Qubit loss, also known as quantum decoherence, is a problem that often occurs when all components in a quantum environment interact with the system, resulting in the loss of photons. Because quantum networks are still in their early stages, scientists don’t yet know how to prevent or repair decoherence, but researchers continue to study its causes.
Quantum vs. Classical Internet Speeds
Traditional internet speeds range from Mbps to Gbps. Mbps speeds are suitable for basic internet activities such as web browsing, sending emails, and streaming media. Gbps speeds enable more bandwidth-intensive use cases such as file downloads, video conferencing, and gaming.
Early theories predicted quantum communication would be faster than the speed of light, but current research suggests this is not the case. Researchers believe that quantum communication violates the principle of causation, which states that every cause has an effect. Quantum communication violates this principle because entanglement (the property that connects qubits together to enable communication between them) can occur no matter how far apart the qubits are.
Quantum entanglement requires that the states of two qubits be directly dependent on each other. In theory, qubits could be a billion miles apart from each other, but they could communicate with each other instantly. Since quantum entanglement shows that it is impossible to measure the position and momentum of entangled particles simultaneously, it is unlikely that the quantum internet is moving at the speed of light.
Quantum vs. Classical Internet Comparison
The table below summarizes the differences between the quantum internet and the classical internet.
| feature | classic internet | as much as the internet |
| data unit | A small amount | Qubit |
| operating mode | TCP/IP protocol suite | Principles of Quantum Mechanics |
| Coverage | Global | Smaller, there are some quantum computing networks |
| Security Protocol | IPsec, VPN, SSL, SSH, TLS, WPA | QKD, quantum secure direct communication, quantum cryptography protocol |
| reliability | High, but there is packet loss | Low, often requires error correction codes |
| speed | Mbps to Gbps |
Theoretically high |
| progress status | 5.4 billion users worldwide | imaginary |
How the quantum and classical internet work together
Researchers expect that the quantum internet and the classical internet will work together to solve complex problems. Some of the ways the quantum internet and classical internet could work together include creating quantum hybrid networks, supercomputing or superconducting bits.
Quantum Hybrid Network
Quantum hybrid networks implement elements of the classical Internet and quantum networks in a single network. Integration can extend security through QKD. The no-cloning theorem prevents duplicate copies of any quantum state from being generated, but redundancy is necessary in an enterprise environment. Furthermore, quantum networks are prone to errors. Network administrators can deploy error correction devices in quantum networks to eliminate errors.
Quantum internet could surpass supercomputing
Terms quantum network and supercomputing They may seem related, but in fact, supercomputers are a classic use case for the Internet. A supercomputer is a general-purpose machine that operates on a bit-by-bit basis to perform lengthy, complex calculations and process large amounts of data. Even in its infancy, the quantum internet could help quantum computers surpass supercomputers’ decade-long legacy in real time.
Superconducting drill bit
Superconducting Quantum Computing The integration of superconductors and quantum networks is described. In other words, superconducting bits are implemented in superconducting circuits. Superconductors replace semiconductor hardware. Experts predict that the quantum internet will run on superconducting-based devices in the future to enable quantum cloud computing.
Quantum Internet: Web x.0
The classic Internet first evolved into Web 1.0 in the 1990s and provided users with static control over the Internet. The second phase, Web 2.0, is a dynamic social media revolution focused on connecting users. The latest iteration, Web 3.0, focuses on decentralization and ownership.
Experts visualize the concept of Web 4.0 as the integration of artificial intelligence in the physical and virtual worlds. The quantum internet may be one step ahead of Web 4.0 or any other advanced stage of future web iterations. Quantum internet could lead to a hacker-free, fast and non-replicable internet.
Venus Kohli is an electronics and telecommunications engineer who obtained her engineering degree from the Bharati Vidyapeeth College of Engineering, University of Mumbai in 2019. Kohli is a technical writer in electronics, electrical, networking and various other technology categories.