### Quantum Information Transfer - recent developments

Quantum networking will most likely have a significant impact on security and the internet.
Recently researchers from Imperial College London, the University of Southampton, and the Universities of Stuttgart and Würzburg have achieved a first successful information transfer with quantum entanglement. This could be an important step developing quantum networks for distributed computing and secure communication.

### What happened and why is it interesting?

**Quantum Information Transfer**:
The team produced, stored, and retrieved quantum information using regular optical fibers. This was made possible by interfacing two key components: a device that creates quantum information and a quantum memory device.
Traditional telecommunications use repeaters to combat information loss over long distances. However, classical repeaters can't be used with quantum information. The researchers overcame this by sharing quantum information in the form of entangled qubits and ensuring compatibility between the quantum dot light source and the quantum memory.

### What’s a Qubit?

Quantum bits (as opposed to classical bits) are the building blocks of quantum data.
Qubits can be based on ions, hydrogen, electrons or photons in a vacuum electromagnetic field, where the number of the particles are equal to the number of qubits.

### Superposition

Quantum particles can exist in a state known as superposition, where they can be 0, 1, or both 0 and 1 simultaneously to varying degrees. This means that a qubit doesn't just hold a binary value but rather a complex probability distribution of these values. When a qubit is measured, it collapses into one of the two definite states (0 or 1), but until that measurement, it effectively holds both possibilities at once.

For example, a qubit in an “equal superposition” has a 50/50 chance of being measured as either 0 or 1.

### The Magic of Quantum Entanglement

Quantum particles, like photons, can become entangled. Two particles are connected and their states are interdependent, meaning the state of one particle is directly related to the state of the other, no matter the distance between them

**Multiple particles/qubits can also become entangled,** a property that is fundamental to quantum networking. When you have multiple qubits, the number of possible states grows exponentially. For nnn qubits, the system can exist in a superposition of 2n2^n2n states. For example:

**With one qubit, you have a superposition of two states (0 and 1).****With two qubits, you have a superposition of four states (00, 01, 10, and 11).****With 20 qubits, the system can exist in a superposition of over a million states.****With 300 qubits, the number of possible states exceeds the number of atoms in the observable universe.**

Each additional qubit doubles the number of possible states the system can be in.

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Why is this so cool?
It makes networks and encryptions ultra-secure!

Today’s networks are vulnerable to hacks, but Quantum networks could enable a different kind of security. Because of the properties of quantum states, it is possible to detect with certainty if a communication has been intercepted. Remember the superposition? When you observe or measure a particle/qubit you lock it into a state. So the act of measuring the quantum state will disturb it, making it detectable. This ensures a new level of security on the internet, safeguarding against hacks and even the threat of more powerful quantum computers that could break current encryption protocols.

### What is Quantum Networking?

Quantum networking involves connecting quantum devices to create a network that utilizes quantum entanglement to allow particles to become interconnected such that the state of one particle instantly influences the state of the other, regardless of the distance between them.
However, this progress is problematic because of loss of quantum information over long distances. One solution is to divide the network into smaller segments connected by a shared quantum state.

Achieving this requires a method to store and retrieve quantum information: a quantum memory device. This device must communicate with another that generates quantum information.

Researchers have successfully developed a system that interfaces these key components and uses regular optical fibers to transmit quantum data for the first time.

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The Misconception of Zero Latency

While quantum entanglement allows for instantaneous state correlation between entangled particles, it doesn't translate to zero latency communication for transferring usable information. Transmitting information still relies on classical communication channels, which are bound by the speed of light. Therefore, while quantum networks can significantly enhance security and potentially reduce some delays, they do not achieve zero latency communication.

### So what do you need to create a Quantum Networking?

A quantum network consists of several key components:

**Quantum Nodes**: Devices that create, manipulate, and measure quantum states.**Quantum Channels**: Physical mediums like optical fibers used to transmit quantum states.**Quantum Repeaters**: Devices that extend the range of quantum communication by mitigating loss and errors in the transmitted quantum information.

### Outlook on the future

Quantum networking could be a giant step forward in technology that could transform our communicaton and the internet in a fundamental way.

By using the basics of quantum mechanics and the power of entanglement, we could create networks that are as secure as possible. Just as AI has changed image creation, quantum technologies are ready to redefine communication, opening up new opportunities.

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