What is a Quantum Internet and what does it mean for regular internet users?
What is a quantum internet?
In the simplest of terms, a quantum internet would be one that uses quantum signals instead of radio waves to send information. The internet we know and love uses radio waves to connect multiple computers through a 'world-wide-web' in which electronic signals are sent back and forth. In a quantum internet, signals would be sent through a quantum network using quantum particles - like photons (particles of light).
What does a quantum internet mean for regular internet users?
As far as typical internet surfing goes, probably not much. It’s highly unlikely that you’ll be using the quantum internet to update Twitter for example. The quantum internet would excel, however, at sending information securely. Through what’s known as quantum encryption or quantum cryptography, people would be able to send “unhackable” data over a quantum network. This is because quantum cryptography sends an encrypted message and its keys separately. Quantum physics means that tampering with the message causes it to change, which something both the sender and receiver can detect. Work on how to send these "un-hackable" signals is being conducted by NQIT
Are we close?
Scientists and engineers have recently made huge strides in building this quantum communication network. China launched the world’s first quantum communication satellite last year, and more recently they conducted the first unhackable video call with it between Beijing and Vienna.
Anything else it can be used for?
A quantum internet could also speed up access to a working quantum computer by putting quantum computing in the cloud. Instead of trying to get your hands on a physical quantum computer, (which are fragile and hard to make) you could access one through the cloud or interface separate quantum computers around the world to boost computing power.
The reference against which other clocks are evaluated
NPL's leading-edge optical atomic clocks have stabilities and uncertainties that surpass the performance of present-day primary frequency standards. As national standards, they provide the reference against which other clocks are evaluated. Building on the expertise gained in developing these laboratory systems, NPL are now engineering portable and compact versions, which will bring improved frequency and timing precision to navigation, sensing, communications and space-based applications.
Optical clocks generate a frequency output in the form of ultra-stable laser light. These frequencies are at several hundred terahertz, but can be divided down into microwave or radio frequencies, without loss of precision, using optical frequency combs. Optical clocks are at the leading edge of performance for both uncertainty and stability in frequency standards.
NPL is working on laboratory-based systems that will be used for the highest accuracy realisation of SI units, contributing to international time scales and ensuring consistency of time and frequency measurements around the globe. They are also used to test fundamental physical theories at unprecedented levels of precision. These compact and portable optical clocks will find much wider use; for example they could provide improved autonomy of on-board clocks in future satellite navigation systems. They could also be used as sensors of gravity potential for oil and mineral surveying or for monitoring volcanic activity, ocean currents and rising sea levels.
Key facts and data
- NPL optical clock types: Sr, Sr+ and Yb+
- Frequency uncertainty: approaching 1 part in 1018
- Frequency stability: approaching 1 part in 1016 at 1 s averaging time
- Future gravity potential sensing capability corresponding to 1 cm height change at the Earth’s surface
Could quantum uncertainty provide the ultimate defence against cybercrime?
Data and communications security are absolutely essential today - for individuals, institutions, businesses, governments and nations. Current secure communications systems have vulnerabilities, some already exposed today and others that may become apparent in the future as computing power and hacking techniques improve. Secure communications based on quantum physics can eliminate some of these vulnerabilities, providing systems whose security is underpinned by the laws of nature. The basic features of quantum physics that enable secure communications are that information encoded in a quantum system cannot be copied; and that information encoded in a quantum system is irreversibly changed when somebody reads it, so that no hacking goes undetected.
Researchers in the UK Quantum Communications Hub are developing such quantum secure communications technologies (for example, quantum key distribution – QKD) for a range of applications and users: from government agencies and industry to commercial establishments and all of us at home. In particular, we are trying to miniaturise quantum systems to make them cheaper to produce and purchase, and easier to incorporate on mobile phones and home computers through quantum chips. We are working towards quantum secured banking apps and ATM facilities to counteract online fraud. And we are building a UK Quantum Network to help incorporate quantum security into the conventional telecommunications infrastructure.
Could quantum physics hold the (secret) key to defeating hackers?
Quantum Key Distribution (QKD) is a currently available technology for the secure distribution of secret keys, used for data encryption. Quantum physics dictates that at the scale of individual particles (for example, photons - particles of light), their quantum properties cannot be measured without being unavoidably and irrevocably disturbed from their original state. This means that no interceptor (or “hacker”) can eavesdrop on quantum secured transmissions, or attempt to copy them, without their presence becoming known to the communicating parties. This disturbance is due to a principle known as quantum uncertainty and it is a fundamental feature of quantum physics. It underpins all current work in the field of quantum communications.
The two communicating parties use transmitted information to distil random data (or “keys”) that only they know. QKD systems generate such shared secret keys, which can then be used for data encryption and other applications. The key generation, distribution and replenishment is underpinned by quantum uncertainty, thus offering to any two communicating parties security based on the laws of quantum physics.
Although proven to work, currently QKD systems are bulky, costly to manufacture and have some limitations. We are working towards overcoming these, enabling widespread use and adoption.