Quantum computing promises to be a revolutionary tool, making short work of equations that classical computers would struggle to ever complete. Yet the workhorse of the quantum device, known as a qubit, is a delicate object prone to collapsing.

Keeping enough qubits in their ideal state long enough for computations has so far proved a challenge.

In a new experiment, scientists were able to keep a qubit in that state for twice as long as normal. Along the way, they demonstrated the practicality of quantum error correction (QEC), a process that keeps quantum information intact for longer by introducing room for redundancy and error removal.

The idea of QEC has been around since the mid-90s, but it's now been shown to work in real time. Part of the reason for the experiment's success was the introduction of machine learning AI algorithms to tweak the error correction routine.

"For the first time, we have shown that making the system more redundant and actively detecting and correcting quantum errors provided a gain in the resilience of quantum information," says physicist Michel Devoret, from Yale University in Connecticut.

Qubits are objects as they exist in a mix of quantum states. Where classic objects can have absolute states, a qubit's version of the same state would be best described using probability. As a qubit interacts with other qubits, their probabilities become entangled in computationally useful ways.

Unfortunately, it's not just other qubits that can entwine their states with a non-decided object. Everything in the environment acts as 'noise', potentially influencing those delicate probabilities and making room for errors.

Part of the reason scientists have struggled to implement QEC is because it can introduce errors of its own. The extra space afforded for error correction can make the qubit even more vulnerable to interference from the surrounding environment.

Like many quantum physics experiments, this one was run at ultra-cold temperatures a hundred times colder than outer space, in this case. The setup has to be carefully controlled in order to protect the qubit as much as possible.

The error-corrected qubit lasted for 1.8 milliseconds only a blink as we might experience it, but an impressive span for a qubit operating on the quantum level. Now the research team will be able to refine the process further.

"Our experiment shows that quantum error correction is a real practical tool," says Devoret. "It's more than just a proof-of-principle demonstration."

While scientists are making significant strides forward in the development of quantum computers and there are rudimentary quantum computers in use now there's still a long way to go before the full potential of the technology is realized.

Reducing noise, improving stability, and upgrading error correction are all going to play a big part in getting closer towards full-scale, practical quantum computers that everyone can use.

In this case the breakthrough was down to several different factors, rather than one change. The QEC code was actually one from 2001, but improvements to it as well as upgrades to the quantum circuit fabrication process made a difference.

"There is no single breakthrough that enabled this result," says Volodymyr Sivak, a research scientist at Google and formerly at Yale University. "It's actually a combination of a whole bunch of different technologies that were developed in the past few years, which we combined in this experiment."

"Our experiment validates a cornerstone assumption of quantum computing, and this makes me very excited about the future of this field."

The research has been published in Nature.

Link:
Physicists Extend Qubit Lifespan in Pivotal Validation of Quantum Computing - ScienceAlert

India can leverage its robust and secure digital public infrastructure to emerge as a force to reckon with in the global manufacturing space, says Rahul Mahajan, who is the CTO ofdigital engineering major Nagarro.In an interaction with businessline, Mahajan also shared his views and insights on recent developments in the field of quantum computing, cloud governance and the impact of AI technology, among others. Excerpts:

5G is finally here. How do you see it changing the IoT, Edge Computing and Cloud landscape? And what does Industry 4.0 mean for India, which is nurturing ambitions of becoming the manufacturing hub of the world?

5G has started disrupting the technology landscape by enabling faster and more reliable communication between devices and systems. With its ultra-low latency and super-high bandwidth capabilities, 5G can support multiple devices, allowing for the development of more complex and sophisticated IoT applications. India is currently in a fortunate position to possess a resilient and secure digital public infrastructure, which is bolstered by key pillars such as the Unified Payments Interface (UPI), Aadhaar, Goods and Services Tax Network (GSTN), Digital Locker, widespread mobile phone adoption, and the National Optical Fibre Network (NOFN). Digital infrastructure plays a fundamental role in driving high growth and a robust economy, fuelled by strong domestic consumption. India is currently striving to establish itself as a dominant force and a global leader in the manufacturing sector. To attain high levels of efficiency in manufacturing, it is crucial to adopt industrial-grade public/private 5G networks, IoT, Edge Computing and cloud-based data analytics, which can effectively enhance operations and promote the transition towards smarter factories (Industry 4.0). With the help of real-time data processing, machine learning, and AI, smart factories can improve quality control, reduce downtime, and increase overall efficiency.

Along with A1, quantum computing is expected to drive the next wave of innovation and enhance productivity across multiple sectors, with some experts saying 2026 or 2027 will be the year when the tech would reach critical maturity. Are we on track for this?

Though quantum computing can be a disruptive technology, it is still an emerging technology. The development of quantum computers is a complex process that requires overcoming several technical hurdles such as decoherence, error correction and scalability. With the current pace of innovation, we hope to achieve Quantum Advantage which is a significant improvement in quantum algorithm runtime for practical cases over the best classical algorithm by the year 2026.

Governments and organisations worldwide are heavily investing in the research and development of quantum computing. For instance, India has launched a National Mission on Quantum Technologies and Applications aimed at advancing quantum technologies in the country. Additionally, India recently revealed a Quantum Communication Network to facilitate secure transmission. Several organisations, including Nagarro and IIT-Madras, are conducting research to develop new solutions using quantum computing.

Apart from encryption, early research in quantum computing has shown potential in areas such as portfolio and asset planning in finance; protein folding and new drug molecule discovery in healthcare; and optimization-related solutions in industries such as retail and manufacturing. In my opinion, although India has made some progress, it should intensify its efforts in quantum computing research. Collaborative work between academia and the corporate industry could lead to tangible results. Encouraging new research papers, patents, and start-ups in this field would also be beneficial.

Whats your take on multi-cloud and hybrid-cloud strategy? How is the model evolving across the world and in India?

Multi-cloud refers to the practice of using more than one cloud provider to meet different requirements, while hybrid-cloud refers to the combination of on-premises infrastructure with one or more cloud providers. A multi-cloud strategy provides greater flexibility and opportunities to reduce cost, reduce the risk of downtime and mitigate the risk of vendor lock-in.

On the enterprise computing side and applicable in the Indian context communications, media, services, and banking/insurance industries are among the top contributors to carbon emissions. There is a growing trend in India and around the world towards prioritising ESG (Environmental, Social, and Governance) considerations and sustainable practices in all aspects of business, including cloud computing. An effective approach is to migrate workloads to the cloud providers where green energy usage is encouraged. We see hyperscalers investing significantly to become greener through measures such as sourcing green energy themselves.

Has the cloud governance model matured? What are the existing and emerging challenges and how do you plan to address them, particularly issues around data security and privacy?

The cloud governance model has been improving over time. Opportunities to further improve governance revolve largely around data security and data privacy. One critical aspect of governance is ensuring that data on the cloud is protected, including encrypting data at rest and in transit, controlling access to data, and monitoring for unauthorised access. Cloud service providers typically have their security measures in place, but it is still important for organisations to have their security policies and procedures to ensure that data is protected.

Another aspect is ensuring compliance with regulatory requirements, such as Indian data protection laws, GDPR or HIPAA. Organizations must ensure that they are following the appropriate regulations when storing and processing data in the cloud. Most organisations are yet to operationalise a clear strategy for progressive consent management, data security operations and use-case-specific data activation. To address these challenges, organizations are exploring best practices, including agile data audits, multi-factor authentication, muti-level encryption, data privacy and security-focused vendor contracts, and enabling a chief data office.

Thanks to ChatGPT, AI has caught the imagination of everyone. How do you see AI improving and optimizing data centre performance?

The recent advancements in AI, particularly in the field of large language models and generative AI, have created a significant potential for enhancing data centre efficiency. With the help of language models, it is now possible to gain unique insights into server logs and network traffic, which can assist data centre solution engineers in developing customised strategies for optimising performance. Additionally, generative AI, such as the technology used in ChatGPT, can be utilised to generate simulated data security scenarios, which can aid in identifying potential security risks proactively.

One of our clients is utilising AI for anomaly detection to prevent excessive billing by monitoring resource consumption and usage. Moreover, we have implemented AI algorithms that proactively adjust server parameters for cooling and power usage to improve energy efficiency. AI is enabling newer ways to solve these problems and we are super excited about the future possibilities.

Link:
India should intensify its efforts in quantum computing research - BusinessLine

In October 2019 a sensational announcement by Google claimed that it had achievedQuantum Breakthrough it had developed and harnessed a quantum computer to solve a problem in seconds, that would have taken conventional computers hundreds of years.

Ever since, there has been a global race among a handful of nations to harness quantum computing to further their own development goals.

India embarked on its own national Quantum-enabled Science & Technology (QuEST) programme and a key priority was the harnessing of Quantum technology fordeveloping highly secure and encrypted communication systems. (What is Quantum Computing and Quantum communication?See primer at end of this article).

That mission was brought a step closer to fruition last week, by ateam of researchers at the Raman Research Institute (RRI) in Bengaluru.

Founded in 1948 by the Indian physicist and Nobel Laureate, CV Raman, the institute since 1972 has functioned as an autonomous research institution of the Government of Indias Department of Science and Technology (DST).

Working in collaboration with the U.R. Rao Satellite Centre of the Indian Space Research Organisation (ISRO) also based in Bengaluru,a team at the Quantum Information and Computing(QuIC) Lab ofthe RRIhas successfully demonstrated a secure channel of communication between a stationary source and a moving platform.

The significance of this breakthrough cannot be overstated:

Just over a year ago the same team demonstrateda similar communication channel between two fixed locations on campus.

By improving on this, to make one of the locations mobile,the researchershave now brought closer,their eventualmission of a secure quantum communication channel between a fixed station on earth and an orbiting satellite.

To maintain communication with a moving platform,the QuIC team developed a Pointing, Acquisition and Tracking (PAT) system, for the stationarysourcewhich must at all times remain in the Line of Sight of the moving platform.

This in itself is not unusual and is a feature of satellite communications.

What is unique to the RRI work is that it established a secure linkbetween fixed and moving stations, using what is known as Quantum Key Distribution (QKD). This is the first time this has been achieved in India, saysproject leader, Urbasi Sinha.

She explains To mimic satellite motion, we progressed from a home-built linear track to a circular track and then built an entire moving vehicle carefully aligned to the receiver.

Why QKD?

Classical cryptography the coding and decoding of messages, as practiced today involves encrypting and sending a message and then decrypting it at the receiving end, using a combo of public and private keys.

These keys depend for their strength on their length and the complicated math they are based on.

But with supercomputers becoming more powerful by the day and more portable public keys are increasingly breakable.This is where Quantum Keysare superior.

Quantum computing, unlike conventional digital computers, doesn'twork with digital ones and zeroes. Quantum bitsor Qubits as they are known,can be a one or a zero at the same time. That means with two Qubits you have four possible states.

The beauty of this, is that it is much more difficult for a hacker to tell if a particular bit is a one or a zero at any given time.

In Quantum Key Distribution, encrypted data is sent in the old fashioned way,but the keys to decrypt them are sent as Quantum bits. It makes the entire chunk of data much harder to hack or crack and this is what the team at RRI has achieved, albeit over a fairly short distance.

QKD is currently the most secure means of facing any threats from efforts at breaking the algorithms of classical computingcryptography, adds Prof Sinha.

Think of it this way (illustration above): In classical digital cryptography, when Alice communicates with Bob,there is the danger of Eve eavesdropping.

Quantum communication using Quantum Key Distribution,makes the task of Eve, well nigh unachievable.

By establishing that India canharness the superior security of quantum cryptography and establish such secure links with mobile platforms, the researchers in Bengaluru, have brought nearer the day when such ultra secure links can be extended to satellite-based communication.

The implications for military communications are obvious.

Quantum Primer

Quantumcomputingis a technology that harnesses the laws of quantum mechanics to solve problems socomplex thatclassicalsupercomputers arentsuper enough to solve them.

Quantum processors work with Qubits rather than bits to perform operations and they can do this only at very low temperatures, close to absolute zero or minus 273 degrees Celsius.

Quantum Communicationsis a sub-field of quantum physics, whose most useful application is the ability to send and receive information that is secure against eavesdroppers. It uses a process called Quantum Key Distribution or QKD.

Read the rest here:
Quantum Breakthrough: Scientists At Raman Research Institute Achieve Key Milestone In Pursuit Of Secure Satellite-Based Communications - Swarajya

image:Environmental noise, here represented as a little demon, can affect the state of a quantum computer by changing the phases of various branches of its wave function in an unpredictable fashion; we call this dephasing. Here, the position of the hand of the clock represents the phase of a particular branch of the wave function. Its modification, not known to us, will affect the delicate ballet of phase recombination which quantum computations rely on. view more

Credit: L. Lami

Researchers Ludovico Lami (QuSoft, University of Amsterdam) and Mark M. Wilde (Cornell) have made significant progress in quantum computing by deriving a formula that predicts the effects of environmental noise. This is crucial for designing and building quantum computers capable of working in our imperfect world.

The choreography of quantum computing

Quantum computing uses the principles of quantum mechanics to perform calculations. Unlike classical computers, which use bits that can be either 0 or 1, quantum computers use quantum bits, or qubits, which can be in a superposition of 0 and 1 simultaneously.

This allows quantum computers to perform certain types of calculations much faster than classical computers. For example, a quantum computer can factor very large numbers in a fraction of the time it would take a classical computer.

While one could naively attribute such an advantage to the ability of a quantum computer to perform numerous calculations in parallel, the reality is more complicated. The quantum wave function of the quantum computer (which represents its physical state) possesses several branches, each with its own phase. A phase can be thought of as the position of the hand of a clock, which can point in any direction on the clockface.

At the end of its computation, the quantum computer recombines the results of all computations it simultaneously carried out on different branches of the wave function into a single answer. The phases associated to the different branches play a key role in determining the outcome of this recombination process, not unlike how the timing of a ballerinas steps play a key role in determining the success of a ballet performance, explains Lami.

Disruptive environmental noise

A significant obstacle to quantum computing is environmental noise. Such noise can be likened to a little demon that alters the phase of different branches of the wave function in an unpredictable way. This process of tampering with the phase of a quantum system is called dephasing, and can be detrimental to the success of a quantum computation.

Dephasing can occur in everyday devices such as optical fibres, which are used to transfer information in the form of light. Light rays travelling through an optical fibre can take different paths; since each path is associated to a specific phase, not knowing the path taken amounts to an effective dephasing noise.

In their new publication in Nature Photonics, Lami and Wilde analyse a model, called the bosonic dephasing channel, to study how noise affects the transmission of quantum information. It represents the dephasing acting on a single mode of light at definite wavelength and polarisation.

The number quantifying the effect of the noise on quantum information is the quantum capacity, which is the number of qubits that can be safely transmitted per use of a fibre. The new publication provides a full analytical solution to the problem of calculating the quantum capacity of the bosonic dephasing channel, for all possible forms of dephasing noise.

Longer messages overcome errors

To overcome the effects of noise, one can incorporate redundancy in the message to ensure that the quantum information can still be retrieved at the receiving end. This is similar to saying Alpha, Beta, Charlie instead of A, B, C when speaking on the phone. Although the transmitted message is longer, the redundancy ensures that it is understood correctly.

The new study quantifies exactly how much redundancy needs to be added to a quantum message to protect it from dephasing noise. This is significant because it enables scientists to quantify the effects of noise on quantum computing and develop methods to overcome these effects.

Computational simulation/modeling

Not applicable

Exact solution for the quantum and private capacities of bosonic dephasing channels

6-Apr-2023

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

See the original post here:
How to overcome noise in quantum computations - EurekAlert

Huge waves of interest are being generated by the development of powerful quantum computers by a select group of the worlds leading companies. So much so that a (quite beautiful) quantum computer recently made it onto the cover of Time Magazine. Here, our expert Chris Lester explores the history of this fascinating field and asks what makes quantum computers quantum?

The age of quantum and computers

The exact starting point of the quantum age is difficult to pinpoint, but its fair to say that many of the theoretical underpinnings of quantum mechanics were first identified in the early 20th century. In the first decade of that century, Max Planck and Albert Einstein both found that they could more accurately explain physical phenomena concerning light and matter (blackbody radiation and the photoelectric effect) by assuming that light is quantised in discrete packets of energy.

Later developments by many others demonstrated the surprising result that light and physical matter can exhibit properties of both particles and waves. This wave-particle duality led to the discovery of many unexpected effects, including quantum tunnelling, where (for example) an electron can leap to the other side of a barrier that according to the pre-quantum theories the particle really doesnt have enough energy to overcome. Rather than being of purely academic or intellectual interest, quantum tunnelling has found real-world application in tunnel diodes a type of semiconductor device that exhibits negative differential resistance.

The 20th century also saw the dawn of the age of digital computers, from early systems that filled entire rooms to the smartphones of today, carried in the pockets of billions of people. This rapid development has been driven by the well-known trend of being able to fit ever more transistors of ever smaller sizes onto a single chip. As famously noted by Richard Feynman, as electronic components used in computers reach ever-smaller microscopic scales, the unusual effects predicted by quantum mechanics are likely to become increasingly important. Its therefore tempting to ask (as Feynman did) whether the strange effects of the quantum world could be exploited to make more powerful computers?

A quantum (ish) computer?

A quantum computer is often described as a device that exploits the quantum mechanical properties of matter to perform computations. So, does this mean that all modern computers which rely on subatomic particles having a distinctly quantum character are, to some extent, quantum computers?

Take for example the computer circuit disclosed in UK patent application GB952610A, first published in 1964, which uses tunnel diodes to perform calculations. The circuit receives two signals consisting of binary bits (0s and 1s) and the negative differential resistance (a key characteristic of the tunnel diodes) is used to add the two signals together. The tunnel diodes exploit the quantum mechanical effect known as quantum tunnelling and the circuit uses these quantum-mechanical tunnel diodes to perform calculations. So does this qualify the circuit in GB952610A as a kind of quantum computer? Or is there something missing?

Quantum all the way down

While its true that all modern digital computers rely on subatomic particles to work and some even use components that exploit quantum mechanical effects many would say that in a truly quantum computer, everything from the encoding of data to the logic of the calculations must be quantum. In other words, a quantum computer must be quantum all the way down.

So even though GB952610A discloses a computer that relies on a quantum mechanical effect (quantum tunnelling) to perform calculations, it still adds together binary bits (0s and 1s). In contrast, for the kinds of computers that are generally described as quantum computers, even the bits themselves are quantum bits, or qubits.

A qubit is a quantum system that has (for example) two levels or states, usually written as 0 and 1. The qubit can be in either state, or unlike the bits in a digital computer in a combination or mixture of both states. Such mixing of states is known as superposition and this is another fundamental idea from quantum mechanics. Being able to manipulate and perform calculations with qubits as opposed to bits opens the door to a whole world of new and exciting possibilities.

New and specialised algorithms that use qubits could one day enable quantum computers to perform calculations much faster than their digital counterparts. For example, Grovers algorithm could allow faster searches to be performed using qubits. In fact, the first experimental demonstration of a quantum computer in 1998 used a 2-qubit quantum computer to implement this very algorithm.

While this early quantum computer was able to solve only the most basic of problems and could maintain coherence for just a few nanoseconds it was the forerunner of the cutting-edge quantum computers (with many dozens of qubits) in use today. And while it may seem that there is a long way to go before quantum computers overtake digital computers in terms of power and computing speed, there exists a real appetite to realise their benefits sooner rather than later.

Rise of the quantum computing era

Although quantum effects have been known and used in computers for quite some time, it seems that the age of quantum computing proper is just getting started. Each year, increasing numbers of patent applications relating to quantum computation are being filed in jurisdictions across the globe, perhaps reflecting the huge sums being invested.

Particularly interesting recent developments include the emergence of hybrid computers those which combine both digital and quantum processors and the expanding list of commercially available systems that are being used by some of the worlds leading companies. From minimising passenger transit times in airports to transforming financial services and detecting fraud, quantum computers are already being used to help solve real-world problems across many industries.

See more here:
What are quantum computers and how 'quantum' are they? - Lexology