(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)

Jonathan Katz, University of Maryland

(THE CONVERSATION) In early July, Google announced that it will expand its commercially available cloud computing services to include quantum computing. A similar service has been available from IBM since May. These arent services most regular people will have a lot of reason to use yet. But making quantum computers more accessible will help government, academic and corporate research groups around the world continue their study of the capabilities of quantum computing.

Understanding how these systems work requires exploring a different area of physics than most people are familiar with. From everyday experience we are familiar with what physicists call classical mechanics, which governs most of the world we can see with our own eyes, such as what happens when a car hits a building, what path a ball takes when its thrown and why its hard to drag a cooler across a sandy beach.

Quantum mechanics, however, describes the subatomic realm the behavior of protons, electrons and photons. The laws of quantum mechanics are very different from those of classical mechanics and can lead to some unexpected and counterintuitive results, such as the idea that an object can have negative mass.

Physicists around the world in government, academic and corporate research groups continue to explore real-world deployments of technologies based on quantum mechanics. And computer scientists, including me, are looking to understand how these technologies can be used to advance computing and cryptography.

In our regular lives, we are used to things existing in a well-defined state: A light bulb is either on or off, for example. But in the quantum world, objects can exist in a what is called a superposition of states: A hypothetical atomic-level light bulb could simultaneously be both on and off. This strange feature has important ramifications for computing.

The smallest unit of information in classical mechanics and, therefore, classical computers is the bit, which can hold a value of either 0 or 1, but never both at the same time. As a result, each bit can hold just one piece of information. Such bits, which can be represented as electrical impulses, changes in magnetic fields, or even a physical on-off switch, form the basis for all calculation, storage and communication in todays computers and information networks.

Qubits quantum bits are the quantum equivalent of classical bits. One fundamental difference is that, due to superposition, qubits can simultaneously hold values of both 0 and 1. Physical realizations of qubits must inherently be at an atomic scale: for example, in the spin of an electron or the polarization of a photon.

Another difference is that classical bits can be operated on independently of each other: Flipping a bit in one location has no effect on bits in other locations. Qubits, however, can be set up using a quantum-mechanical property called entanglement so that they are dependent on each other even when they are far apart. This means that operations performed on one qubit by a quantum computer can affect multiple other qubits simultaneously. This property akin to, but not the same as, parallel processing can make quantum computation much faster than in classical systems.

Large-scale quantum computers that is, quantum computers with hundreds of qubits do not yet exist, and are challenging to build because they require operations and measurements to be done on a atomic scale. IBMs quantum computer, for example, currently has 16 qubits, and Google is promising a 49-qubit quantum computer which would be an astounding advance by the end of the year. (In contrast, laptops currently have multiple gigabytes of RAM, with a gigabyte being eight billion classical bits.)

Notwithstanding the difficulty of building working quantum computers, theorists continue to explore their potential. In 1994, Peter Shor showed that quantum computers could quickly solve the complicated math problems that underlie all commonly used public-key cryptography systems, like the ones that provide secure connections for web browsers. A large-scale quantum computer would completely compromise the security of the internet as we know it. Cryptographers are actively exploring new public-key approaches that would be quantum-resistant, at least as far as they currently know.

Interestingly, the laws of quantum mechanics can also be used to design cryptosystems that are, in some senses, more secure than their classical analogs. For example, quantum key distribution allows two parties to share a secret no eavesdropper can recover using either classical or quantum computers. Those systems and others based on quantum computers may become useful in the future, either widely or in more niche applications. But a key challenge is getting them working in the real world, and over large distances.

This article was originally published on The Conversation. Read the original article here: http://theconversation.com/how-quantum-mechanics-can-change-computing-80995.

Continue reading here:

How quantum mechanics can change computing - San Francisco ... - San Francisco Chronicle

- Superconducting quantum computing - Wikipedia - October 6th, 2019
- Quantum computing | MIT News - October 6th, 2019
- How Do Quantum Computers Work? - sciencealert.com - October 2nd, 2019
- What is Quantum Computing? - Definition from Techopedia - October 2nd, 2019
- How Quantum Computers Work | HowStuffWorks - September 5th, 2019
- Quantum computing could change everything, and IBM is ... - May 15th, 2019
- Quantum Computing - Intel - April 29th, 2019
- IBM expands universities in its quantum computing research ... - April 25th, 2019
- Quantum computing is a marathon not a sprint | VentureBeat - April 22nd, 2019
- The CIO's Guide to Quantum Computing - Smarter With Gartner - April 19th, 2019
- This Startup Just Raised $21 Million To Bring Quantum ... - April 18th, 2019
- What is Quantum Computing ? Top 18 Quantum Computing ... - April 6th, 2019
- The promise of quantum computing - businessinsider.com - March 27th, 2019
- Quantum computing is coming: Heres why we need to get our ... - March 23rd, 2019
- Quantum computing will break your encryption in a few ... - March 21st, 2019
- Microsoft has formed a coalition to promote quantum computing ... - March 19th, 2019
- Quantum computing for everyone | Michael Nielsen - March 12th, 2019
- Ask a Techspert: What is quantum computing? - blog.google - March 6th, 2019
- IBM hits quantum computing milestone, may see 'Quantum ... - March 6th, 2019
- Its Time You Learned About Quantum Computing | WIRED - March 6th, 2019
- Microsofts quantum computing network takes a giant leap ... - March 2nd, 2019
- When Will Quantum Computing Have Real Commercial Value ... - February 25th, 2019
- The Case Against Quantum Computing - IEEE Spectrum - February 22nd, 2019
- How Does Quantum Computing Work? - ExtremeTech - January 31st, 2019
- Quantum technology - Wikipedia - January 23rd, 2019
- CES 2019: IBM's Q System One Is the Rock Star Quantum ... - January 13th, 2019
- Quantum Computing | The MIT Press - January 11th, 2019
- IBM thinks outside of the lab, puts quantum computer in a box - January 11th, 2019
- IBM unveils its first commercial quantum computer - January 9th, 2019
- A new type of quantum computer has smashed every record ... - December 21st, 2018
- China bet big on quantum computing. Now the US races to ... - October 26th, 2018
- US takes first step toward a quantum computing workforce ... - September 17th, 2018
- China bet big on quantum computing. Now the ... - money.cnn.com - September 17th, 2018
- The reality of quantum computing could be just three years ... - September 12th, 2018
- The quantum computing race the US cant afford to lose - September 3rd, 2018
- Quantum Computing | USRA - August 30th, 2018
- What Is Quantum Computing? The Complete WIRED Guide | WIRED - August 22nd, 2018
- Quantum Computing Market Research Report- Forecast 2022 | MRFR - August 1st, 2018
- Two Quantum Computing Bills Are Coming To Congress - July 5th, 2018
- Senate bills would make quantum computing a priority - June 10th, 2018
- What is quantum computing? - Definition from WhatIs.com - February 5th, 2018
- The Era of Quantum Computing Is Here. Outlook: Cloudy ... - January 26th, 2018
- IBM puts its quantum computer to work in relaxing, nerdy ASMR ... - January 8th, 2018
- Quantum computing is going to change the world. Here's what ... - January 8th, 2018
- Is Quantum Computing an Existential Threat to Blockchain ... - December 25th, 2017
- What is Quantum Computing? | SAP News Center - December 23rd, 2017
- Quantum Computing Explained | What is Quantum Computing? - December 21st, 2017
- New silicon structure opens the gate to quantum computers - December 14th, 2017
- Microsoft offers developers a preview of its quantum ... - December 12th, 2017
- Quantum Computing Is the Next Big Security Risk | WIRED - December 8th, 2017
- Yale Professors Race Google and IBM to the First Quantum ... - November 16th, 2017
- IBM's processor pushes quantum computing ... - engadget.com - November 16th, 2017
- Quantum computing - news.microsoft.com - November 1st, 2017
- Intel Takes First Steps To Universal Quantum Computing - October 13th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - October 13th, 2017
- quantum computing - engadget.com - October 13th, 2017
- Quantum Computing | Intel Newsroom - October 13th, 2017
- What will you actually use quantum computing for? | ZDNet - October 11th, 2017
- Here's what quantum computing is and why it matters - October 6th, 2017
- Microsoft just upped its multi-million bet on quantum computing - ZDNet - September 7th, 2017
- Microsoft's Aussie quantum computing lab set to scale up next-gen ... - ARNnet - September 7th, 2017
- An Entirely New Type of Quantum Computing Has Just Been Invented - Futurism - September 7th, 2017
- Quantum computing event explores the implications for business - Cambridge Network - August 30th, 2017
- Quantum Computing Is Coming at Us Fast, So Here's Everything You Need to Know - ScienceAlert - August 27th, 2017
- Commonwealth Bank investing in Australia's first quantum computer company - Which-50 (blog) - August 25th, 2017
- How quantum mechanics can change computing - The Conversation US - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - Computerworld Australia - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - insideHPC - August 23rd, 2017
- $495.3 Million Quantum Computing Market 2017 by Revenue Source, Application, Industry, and Geography - Global ... - PR Newswire (press release) - August 18th, 2017
- Physicists Have Made Exotic Quantum States From Light - Futurism - August 16th, 2017
- Machine learning tackles quantum error correction - Phys.Org - August 15th, 2017
- Quantum Internet Is 13 Years Away. Wait, What's Quantum Internet? - WIRED - August 15th, 2017
- Blind quantum computing for everyone - Phys.org - Phys.Org - August 12th, 2017
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED - August 12th, 2017
- Quantum Computing Market Worth 495.3 Million USD by 2023 | 08 ... - Markets Insider - August 10th, 2017
- China uses a quantum satellite to transmit potentially unhackable data - CNBC - August 10th, 2017
- Physicists Take Big Step Towards Quantum Computing and ... - Universe Today - August 1st, 2017
- Why you might trust a quantum computer with secretseven over ... - Phys.Org - July 12th, 2017
- Quantum-computer node uses two different ion species - physicsworld.com - July 10th, 2017
- Quantum Computers vs Bitcoin How Worried Should We Be? - The Merkle - July 10th, 2017

## Recent Comments