Monthly Archives: January 2020

XinaBox, Quest for Space To Send Experiments To The International Space Station – Space in Africa

Posted: January 26, 2020 at 11:55 pm

Cape Town-based Xinabox R&D, a developer of modular electronics and IoT kits for rapid prototyping and STEM education, is partnering with U.S-based Quest for Space to launch experiments to the International Space Station (ISS).

The XinaBox experiment alongside 17 other experiments affiliated with the Quest for Space Program will be launched to the ISS on 7 February 2020, onboard a Northrop Grumman NG-13 Launch Vehicle on a resupply mission from NASAs Wallops Flight Facility in Wallops Island, Virginia. Fourteen of these experiment modules are being developed by Partner Schools as part of the Quest for Space Program, one by Texas A & M University, and two Quest Improved Design Qualification Units.

San Jose-based Valley Christian High School, started the Space Lab Program in 2009 to enable students to research, design and build unique science experiments that operate aboard the ISS for a minimum of 30 days. Quest for Space is a non-profit focused on making these and other programs available to schools globally.

In an email chat with Space in Africa, Dan Saldana, Director of ISS and Satellite Programs at Valley Christian Schools, notes that the Space Lab Program was developed to help students identify and enhance their passion by applying their technical and managerial skills in the development of their unique science experiment. The goal is for the students to develop, launch and perform a post-flight analysis on their experiment within the school year.

Since the first launch to the ISS in January 2010 onboard a Japanese HIV-3 ISS Service Vehicle carrying a student plant growth experiment, Quest for Space has expanded its program beyond the shores of the United States, to include partner schools from Finland, Singapore, Indonesia, and Australia. As of today, Quest for Space and its Partner Schools have launched a total of 138 student experiments to the ISS.

The launch in February will include the XinaBox experiment as a pilot to demonstrate cutting-edge technology of the XK92 xChips Xinaboxs latest kit developed for the ISS mission. Schools across the globe will be engaged to concurrently collect data, with their XK92 kit, for data analysis and interpretation on Earth. Student teams will compare their data with that recovered from the ISS XK92, upon its return to Earth on the SpaceX 20 mission.

While onboard the ISS, the XinaBox payload will collect various datasets ranging from temperature to humidity, pressure, volatile organic compounds, g-force and acceleration. The datasets will be stored on a SD card to be assessed once the experiments return to Earth after some weeks.

The XinaBox payload, just as other Quest for Space experiments, will independently carry out its research after it is unpacked, without requiring assistance from the astronauts on the ISS.

During the mission, schools and engineering clubs within the XinaBox ecosystem will develop and run mirror experiments using the XK92 xChips to collect and analyze data to be compared with the dataset on the SD card from the ISS.

Schools can record more data at the same time, which means that they are not only able to record their data and compare it with the data from the International Space Station, but they can also look at the data from other institutions that have conducted the experiment anywhere in the world, Bjarke Gotfredsen, the inventor and co-founder of XinaBox told Space in Africa.

The idea is to have students in a classroom mirror science experiments conducted on the International Space Station and experience the dream of collecting space data for scientific research, Judi Sandrock, co-founder of XinaBox, said, pointing out that they intend making available the ISS mission payload as a learning kit for schools to build upon.

We would like the students to come up with different ideas of what they could learn from the large selection of valuable data sets collected on the SD card while onboard the ISS. We are looking at the mission from a scientific inquiry perspective. This will spur students curiosity and enable schools to expand the outcomes of the research.

Commenting on how the mission aligns with the goals of the Quest for Space Program, Saldana said the program takes the student from the concept of their idea to the shipping of their final product through analyzing the experimental results upon its return. Students have hands-on experience specifying, designing, and building their one of a kind experiment by meeting defined milestones and presenting their design to NASA Safety for review.

Three things make the XinaBox xChips viable for many more schools around the world. One is that they dont need a lab to put it together. Two, the kit itself is not expensive compared to what people normally send to the International Space Station. Three, because it takes up so little space, it can be easily packaged together with the Quest for Space program. These three factors help to expand or open up space for many more schools, Gotfredsen said.

While the launch in February 2020 is a proof of concept for what Judi Sandrock believes is the first of many in the companys partnership with Quest for Space, it is important to point out that this is not XinaBoxs first orbit experience.

On 17 April 2019, the ThinSat Programme launched a constellation of 55 student picosatellites into space, using XinaBox as the payload to study weather conditions and carry out scientific experiments in Extreme Low Earth Orbits. XinaBox supplied the kits and content for building the picosatellites and supported sixteen schools in the Western Cape of South Africa that collectively developed one of the picosatellites.

Xinabox co-founders believe the new partnership between Quest for Space and XinaBox will broaden opportunities for schools in emerging regions, particularly in Africa, to send experiments to the ISS through the Quest for Space Program.

Judi said the Quest for Space Program is comparatively attractive to schools across the world, adding that the introduction of Xinabox will further lower the cost considerably because the XinaBox xChips take less space and energy.

We look forward to having Partner Schools from Africa and other parts of the world join our Quest for Space Programs, Saldana said.

All of the Quest for Space Lab Partner Schools are invited to attend and compete in the annual American Society for Gravitational and Space Research (ASGSR) Conference student poster competition. The students prepare and present a poster on their experiment to the NASA Research Scientists, and the winners get cash prizes and an opportunity to present to and network with NASAs top research scientists.

The Quest for Space Lab educational research flight opportunity was made available to Valley Christian High School of San Jose, California, via a partnership with the Quest Institute for Quality Education, and by Space Tango who provides both the payload architecture and in-flight operations on the International Space Station.

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ESA, Airbus join forces on the Space Station – Spatial Source

Posted: at 11:55 pm

ESA and Airbus have signed a contract for the Bartolomeo platform on the International Space Station.

The Bartolomeo platform from Airbus opens new opportunities for research on the International Space Station (ISS). The European Space Agency ESA has now booked a payload slot for a Norwegian instrument to monitor plasma density in the Earths atmosphere.

The Bartolomeo platform named after Christopher Columbus younger brother is currently in the final stage of launch preparation at Airbus in Bremen, Germany, and is scheduled for launch to the ISS in March 2020. Bartolomeo is developed on a commercial basis by Airbus using its own investment funds and will be operated in cooperation with ESA.

The platform can accommodate up to 12 different experiment modules, supplying them with power and providing data transmission to Earth. Bartolomeo is suitable for many different experiments. Due to the unique position of the platform with a direct view of Earth from 400 kilometres, Earth observation including trace gas measurements or CO2 monitoring of the atmosphere are possible, with data useful for climate protection or for use by private data service providers.

The Multi-Needle Langmuir Probe (m-NLP) is an instrument from the University of Oslo and the Norwegian company Eidsvoll Electronics to measure ionospheric plasma densities. With its relatively low orbit, the ISS passes near the peak plasma density of the ionosphere. The m-NLP is currently the only instrument in the world capable of resolving ionospheric plasma density variations at spatial scales below one metre. It will gather valuable data from the equatorial and mid-latitude ionosphere, enabling study of the dynamic processes in this region in unprecedented detail. The Langmuir Probe will map plasma characteristics around the globe.

The mission is financed through the ESA PRODEX programme and supported by ESAs Directorate Human & Robotic Exploration. The payload is scheduled to launch on ISS resupply flight NG-14 in October 2020 and will be the first payload to be installed on the Bartolomeo Platform outside the European Columbus Module.

Together with UNOOSA (United Nations Office for Outer Space Affairs), Airbus is currently inviting tenders for further research opportunities on the platform, in particular to enable research institutions from developing countries to participate in scientific space research.

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How SpaceX and Boeing became NASA’s best shot to revive US spaceflight – Business Insider

Posted: at 11:55 pm

SpaceX launched one of its Falcon 9 rockets on Sunday, only to watch it erupt in a ball of fire.

But the explosion was intentional and went exactly as planned. It was the final step in a long process of testing the company's Crew Dragon capsule a spaceship designed to carry astronauts to and from the International Space Station.

Boeing has designed a similar spacecraft, and the two companies are racing to fly NASA astronauts on US-made spacecraft for the first time in nearly a decade.

Since NASA ended its space-shuttle program in 2011, the agency has relied exclusively on Russia to ferry its astronauts to and from orbit in Soyuz spacecraft. But those seats have gotten increasingly expensive: A single round-trip seat now costs NASA about $85 million. So the space agency launched its Commercial Crew program to spur the development of new American-made spacecraft.

The program put private companies in competition for billions of dollars' worth of government contracts. SpaceX and Boeing came out on top.

SpaceX's latest test has teed Elon Musk's rocket company up to launch its first-ever human passengers this spring.

"This critical test puts us on the cusp of once again launching American astronauts on American rockets from American soil," Jim Bridenstine, NASA's administrator, tweeted shortly after the mission.

Here's how SpaceX and Boeing became NASA's best shot at resurrecting American spaceflight.

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French agency CNES to aid ISROs space station project – The New Indian Express

Posted: at 11:55 pm

Express News Service

BENGALURU: The French national space agency National Centre for Space Studies (CNES), which is collaborating with the Indian Space Research Organisation (ISRO) in the Gaganyaan project, will also partner with the latter in the development of Indias planned space station.

A CNES official, speaking on behalf of the president of CNES, Jean-Yves Le Gall, told The New Indian Express that the French agency and its industry partners have gained vast experience from the Automated Transfer Vehicle (ATV) and its spin-offs such as rendezvous operations with the International Space Station (ISS). French and European partners can bring the skills they have acquired in developing and operating systems and dedicated infrastructure for long-term six-month flights of European astronauts on the ISS, he said.

While reiterating support for the Gaganyaan missions, he termed it as "the first step towards future collaboration on the development of Indias planned space station". "We want cooperation between France and India in human spaceflight to evolve into a long-term partnership along the same lines as our 15-year collaboration on climate-monitoring satellites and 50 years of working together on launchers," Le Gall said.

We have confidence in ISROs ability to partner in human space exploration and we are ready to provide all the support we can to develop the space station. This also means India should be closely involved in the future international space station programmes that will succeed ISS, commensurate with its place in the world, he said at an event organised by ISRO in the city recently.

French experts may train Indian astronauts

Meanwhile, teams of CNES and ISRO have finalised drafting the agreement between the two space agencies in which French experts are likely to provide training to Indian astronauts. They are likely to be trained by Novespace, a CNES subsidiary, on parabolic flights aboard the Air Zero Gravity, which is a modified version of an Airbus A310, a CNES official said. This will provide the astronauts a zero-gravity environment on Earth.

Expert services will be provided at CADMOS (the control centre in charge of operating the science and physiological experiments on the ISS) at MEDES space medicine research facility and hospital, in collaboration with ESAs European Astronaut Centre (EAC). The CADMOS conceives and prepares the instruments and equipment that Europes astronauts use on the ISS, the official said.

The four Indian astronauts are set to go to Russias Star City for training, ISRO Chairman K Sivan had told TNIE. The training is said to last for a year (2021) before they return to India for another round of training.The CNES will also provide India equipment for life support that astronauts will wear during Gaganyaan, scheduled for 2022. They will be using several French devices for health monitoring eyewear device featuring a bluetooth connected garment which is equipped with biomedical sensors, aquapad cotton for quick and easy testing of water, specific equipment for waste management, or even food packaging.

They may even use other devices such as the ECHO, an ultrasound system tele-operated by doctors on the ground, or the Cardiomed to measure cardiovascular activity. CNES expert Dr Brigitte Godard has already spent time during July and August in Bengaluru to train physicians and personnel, said the official.

The Indian physicians and engineers involved in Gaganyaan will also be trained in France in the coming months. Training sessions will be for two weeks each, with teams coming and going. The training will be given at MEDES space medicine and physiology institute in Toulouse and by the teams at ESAs astronaut training centre in Cologne.

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French agency CNES to aid ISROs space station project - The New Indian Express

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NASA astronauts to fly SpaceX Crew Dragon in spring how they prepare – INSIDER

Posted: at 11:55 pm

SpaceX is poised to launch its first astronauts into space this spring: Bob Behnken and Doug Hurley.

Their flight on the company's Crew Dragon spaceship will mark the first time an American spacecraft has carried NASA astronauts since the Space Shuttle program ended in 2011.

Behnken and Hurley's liftoff is expected to launch a new era of US spaceflight, since it will allow NASA to stop relying on Russian launch systems to get astronauts into space. It will probably also make the two astronauts the first to ever fly a commercial spacecraft.

"Bob and I were lucky enough to be selected together," Hurley told The Atlantic in September. "As we get closer to launch, things in the last year have actually been pretty hectic. We've been spending increasing amounts of time in California, because that's where most of the work is being done for Dragon."

In preparation, they've run through emergency procedures, undergone extensive training the Crew Dragon's mechanisms, worn their new spacesuits, and met with SpaceX CEO Elon Musk.

"People to a degree think it's pretty glamorous to be able to go into space, but it's actually like a messy camping trip," Hurley told Reuters in June.

Here's how the astronauts were selected and how they're preparing to fly Crew Dragon to the space station.

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LEGO Ideas 21321 International Space Station exclusive patch on the way – Brick Fanatics

Posted: at 11:55 pm

Those who buy LEGO Ideas 21321 International Space Station in its first nine days on sale will get an exclusive patch for free.

First revealed early in January, LEGO Ideas 21321 International Space Station will be released on February 1. In addition to the 864-piece set itself, those who buy the exclusive release at LEGO.com before February 9 will get an exclusive patch for free.

The patch was revealed on the LEGO Store February calendar, which was spotted by the Brick Fan. In the centre of the patch is an image of the new LEGO model, with the flags of all of the countries that participate in the program around the edge.

Brick Fanatics reviews LEGO Ideas 21321 International Space Station.

LEGO fan Christoph Ruge came up with the original product idea and seemed to have missed his chance until the LEGO Ideas selected a handful of past projects for users to vote on for the 10th anniversary, with this model coming out on top.

The LEGO Store Nuremburg, Germany, will host a designer signing event with Christoph on January 31 from 7.00pm until 8.00pm.

We decided that one of these great ideas should have a second chance, so we thought we would turn the LEGO Ideas process upside down, said Hasan Jensen, LEGO Ideas Engagement Manager, when the set was officially announced. This time we started the internal review and came up with four exciting projects that we thought showed the greatest potential and then it was up to the LEGO Ideas community to decide which of the four would be made into LEGO Ideas set number 29. It was great fun to follow the fan vote and we were excited to be able to finally welcome the International Space Station into the LEGO Ideas family.

LEGO Ideas 21321 International Space Station will be available from February 1 at LEGO.com.

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El Paso scientists team up for heart research project at the International Space Station – KVIA El Paso

Posted: at 11:55 pm

EL PASO, Texas -- Biomedical research scientists from Texas Tech University Health Sciences Center El Paso and The University of Texas at El Paso are partnering up to send "artificial mini-hearts" to the International Space Station to better understand how microgravity affects the function of the human heart.

The three-year project, funded by the National Science Foundation (NSF) and the space station's U.S. National Laboratory, brings together TTUHSC El Paso faculty scientist Munmun Chattopadhyay, Ph.D., and UTEP biomedical engineer Binata Joddar, Ph.D. The researchers will collaborate in their Earth-bound labs to create tiny (less than 1 millimeter thick) heart-tissue structures, known as cardiac organoids, using human stem cells and 3D bioprinting technology.

By exposing the organoids to the near-weightless environment of the orbiting space station, the researchers hope to gain a better understanding of a health condition known as cardiac atrophy, which is a reduction and weakening of heart tissue. Cardiac atrophy often affects astronauts who spend long periods of time in microgravity. A weakened heart muscle has difficulty pumping blood to the body, and can lead to problems such as fainting, irregular heartbeat, heart valve problems and even heart failure. Cardiac atrophy is also associated with chronic disease.

The first year of the project, which began in September, will focus on research design. During this phase, Dr. Joddar will use 3D printing to fabricate the cardiac organoids by coupling cardiac cells in physiological ratios to mimic heart tissue. The second year will be centered on preparing the organoid payload for a rocket launch and mission in space. The third and final year of the research will involve analyzing data from the experiment after the organoids are returned to Earth.

The project will also provide an educational opportunity for the El Paso community, with a workshop for K-12 students to learn about tissue engineering projects on the space station. It will also include a seminar for medical students, interns and residents about the benefits and challenges of transitioning research from Earth-based laboratories into space.

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Which Fallout 76 Faction Is Cooler, The Crashed Space Station Or The Log Cabin? – Kotaku

Posted: at 11:55 pm

Fallout 76s upcoming Wastelanders expansion will add two new faction settlements: settlers and raiders. One of these looks like a Lincoln Log fort while the other is made out of a crashed space station. Can you guess which one players are already gravitating towards?

Yesterday, Bethesda shared some screenshots of the two new locations and more information about the people living there. The settlers, led by Paige (the former head of the D.C. Construction Workers Union), are a hard-working, salt of the earth lot who have taken up refuge in Spruce Knob toward the southeastern part of the map. The raiders, meanwhile, have come back to Appalachia to take back territory theyve claimed for themselves before it falls into the hands of the settlers.

Their leader, Meg, looks like shes seen some shit out in the wasteland and probably isnt one for negotiating mutually beneficial deals. The crashed space station she and her gang call home is up in the northern edge of the map, and frankly it looks way more fun. Most raider camps tend to look like if your friend of a friends screamo band played their basement show inside of a scrapyard barbeque pit, but Megs looks like a sci-fi arcade.

In Wastelanders Im going to check out the settlers, wrote one person on Reddit. If they are blowing glass, making electronic components, making their own ceramics...Ill stay. But if its an entire camp of Sturges hammering at the same section of wall for months I think I have to go raider.

Sturges was a synth repairman from Fallout 4 who never did jack shit. Understandably, some players are worried that the big NPC update many are expecting to finally make Fallout 76 good will only repeat some of the last games more uninspired moments. Nothing beats protecting the innocent, but I do envy the raiders and their space station town, wrote another player.

The new characters, dialogue trees, quests, and romance options coming in the Wastelanders update will all be based in one of the two new settlements, with Bethesda heavily implying that a players reputation with one will hurt their reputation with the other, forcing them to choose one over the other.

Based on their sense of style and interior design, Im gonna have to go raiders on this one, despite my deep-rooted commitment to labor solidarity.

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Gaganyaan, space station will pave way for continuous Indian presence in space: ISRO chief – The Hindu

Posted: at 11:55 pm

Gaganyaan, the first Indian human space flight set for 2022, and a subsequent space station would pave the way for continuous Indian presence in space, K. Sivan, Indian Space Research Organisation (ISRO) Chairman and Secretary, Department of Space, said here on Wednesday.

The crewed space mission would also help to build a framework for long-term global partnerships that benefit society in many ways, he said at the inaugural of a three-day international symposium on human space flight.

Gaganyaan was not just an ISRO project. It was a national endeavour that involved numerous agencies, laboratories, disciplines, industries and departments. It was expected that new science will emerge from Gaganyaan and enhance our science and technology capabilities, Dr..Sivan told an international gathering of space experts, decision-makers, associated industries, astronauts and students.

One ISS [International Space Station] put up by multiple countries may not be enough. Regional ecosystems will be needed and Gaganyaan will focus on regional needs: food, water and energy security, he said.

From employment to security [food, energy and so on], most countries have similar goals, and these partnerships can help meet those goals. Benefits from possible spin-offs are aplenty, he observed.

The target of realising Gaganyaan by August 2022, he admitted, was challenging. However, ISRO already has the GSLV-MarkIII as a working launch vehicle. It had proven systems for re-entry and recovery of the crew capsule, space-qualified parachutes for safe descent of crew and was working on a comprehensive emergency escape system for astronauts. The missing systems, namely human life science and support system, are being developed now, he stated.

ISRO is getting four candidate astronauts from the Air Force to train in Russia and taking French assistance for training in their health upkeep during space travel.

K. Vijay Raghavan, Principal Scientific Adviser to the Government of India, referred to the challenges of climate change that warranted coordinated global efforts. Space collaborations, he said, had shown the world how to tackle such international issues.

As for the critical area of life sciences that is important in a human flight, he said that many more studies were needed for a full understanding in spite of numerous astronaut missions.

Key officials from eight space agencies and five astronauts from five countries are in Bengaluru for the event that focusses on the challenges and future trends of human flights.

The symposium is organised by ISRO, the International Astronautical Association (IAA) and the Aeronautical Society of India.

Among the key participants are Joel Montalbano from NASA's ISS Program Office, director of Russian ROSCOSMOS's department of manned spaceflight Alexander Bykov, IAA Secretary General Jean-Michel Contant, French agency CNES's head of the launch vehicle directorate Jean-Marc Astorg, European Space Agency's inter-agency Coordinator Thomas Reiter, Japan Exploration and Space Agency's Director-General of Space flight Technology Shizuo Yamamoto and Romanian Space Agency CEO Marius-Ioan Piso.

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Quantum computing – Wikipedia

Posted: at 11:54 pm

Study of a model of computation

Quantum Computing is the use of quantum-mechanical phenomena such as superposition and entanglement to perform computation. A quantum computer is used to perform such computation, which can be implemented theoretically or physically[1]:I-5 There are two main approaches to physically implementing a quantum computer currently, analog and digital. Analog approaches are further divided into quantum simulation, quantum annealing, and adiabatic quantum computation. Digital quantum computers use quantum logic gates to do computation. Both approaches use quantum bits or qubits.[1]:2-13

Qubits are fundamental to quantum computing and are somewhat analogous to bits in a classical computer. Qubits can be in a 1 or 0 quantum state. But they can also be in a superposition of the 1 and 0 states. However, when qubits are measured the result is always either a 0 or a 1; the probabilities of the two outcomes depends on the quantum state they were in.

Quantum computing began in the early 1980s, when physicist Paul Benioff proposed a quantum mechanical model of the Turing machine.[2]Richard FeynmanandYuri Maninlater suggested that a quantum computer had the potential to simulate things that a classical computer could not.[3][4] In 1994, Peter Shor developed a quantum algorithm for factoring integers that had the potential to decrypt all secured communications.[5]

Despite ongoing experimental progress since the late 1990s, most researchers believe that "fault-tolerant quantum computing [is] still a rather distant dream".[6] On 23 October 2019, Google AI, in partnership with the U.S. National Aeronautics and Space Administration (NASA), published a paper in which they claimed to have achieved quantum supremacy. [7] While some have disputed this claim, it is still a significant milestone in the history of quantum computing.[8]

The field of quantum computing is a subfield of quantum information science, which includes quantum cryptography and quantum communication.

The prevailing model of quantum computation describes the computation in terms of a network of quantum logic gates. What follows is a brief treatment of the subject based upon Chapter 4 of Nielsen and Chuang.[9]

A memory consisting of n {textstyle n} bits of information has 2 n {textstyle 2^{n}} possible states. A vector representing all memory states has hence 2 n {textstyle 2^{n}} entries (one for each state). This vector should be viewed as a probability vector and represents the fact that the memory is to be found in a particular state.

In the classical view, one entry would have a value of 1 (i.e. a 100% probability of being in this state) and all other entries would be zero. In quantum mechanics, probability vectors are generalized to density operators. This is the technically rigorous mathematical foundation for quantum logic gates, but the intermediate quantum state vector formalism is usually introduced first because it is conceptually simpler. This article focuses on the quantum state vector formalism for simplicity.

We begin by considering a simple memory consisting of only one bit. This memory may be found in one of two states: the zero state or the one state. We may represent the state of this memory using Dirac notation so that

The state of this one-qubit quantum memory can be manipulated by applying quantum logic gates, analogous to how classical memory can be manipulated with classical logic gates. One important gate for both classical and quantum computation is the NOT gate, which can be represented by a matrix

The mathematics of single qubit gates can be extended to operate on multiqubit quantum memories in two important ways. One way is simply to select a qubit and apply that gate to the target qubit whilst leaving the remainder of the memory unaffected. Another way is to apply the gate to its target only if another part of the memory is in a desired state. These two choices can be illustrated using another example. The possible states of a two-qubit quantum memory are

In summary, a quantum computation can be described as a network of quantum logic gates and measurements. Any measurement can be deferred to the end of a quantum computation, though this deferment may come at a computational cost. Because of this possibility of deferring a measurement, most quantum circuits depict a network consisting only of quantum logic gates and no measurements. More information can be found in the following articles: universal quantum computer, Shor's algorithm, Grover's algorithm, DeutschJozsa algorithm, amplitude amplification, quantum Fourier transform, quantum gate, quantum adiabatic algorithm and quantum error correction.

Any quantum computation can be represented as a network of quantum logic gates from a fairly small family of gates. A choice of gate family that enables this construction is known as a universal gate set. One common such set includes all single-qubit gates as well as the CNOT gate from above. This means any quantum computation can be performed by executing a sequence of single-qubit gates together with CNOT gates. Though this gate set is infinite, it can be replaced with a finite gate set by appealing to the Solovay-Kitaev theorem.

Integer factorization, which underpins the security of public key cryptographic systems, is believed to be computationally infeasible with an ordinary computer for large integers if they are the product of few prime numbers (e.g., products of two 300-digit primes).[10] By comparison, a quantum computer could efficiently solve this problem using Shor's algorithm to find its factors. This ability would allow a quantum computer to break many of the cryptographic systems in use today, in the sense that there would be a polynomial time (in the number of digits of the integer) algorithm for solving the problem. In particular, most of the popular public key ciphers are based on the difficulty of factoring integers or the discrete logarithm problem, both of which can be solved by Shor's algorithm. In particular, the RSA, DiffieHellman, and elliptic curve DiffieHellman algorithms could be broken. These are used to protect secure Web pages, encrypted email, and many other types of data. Breaking these would have significant ramifications for electronic privacy and security.

However, other cryptographic algorithms do not appear to be broken by those algorithms.[11][12] Some public-key algorithms are based on problems other than the integer factorization and discrete logarithm problems to which Shor's algorithm applies, like the McEliece cryptosystem based on a problem in coding theory.[11][13] Lattice-based cryptosystems are also not known to be broken by quantum computers, and finding a polynomial time algorithm for solving the dihedral hidden subgroup problem, which would break many lattice based cryptosystems, is a well-studied open problem.[14] It has been proven that applying Grover's algorithm to break a symmetric (secret key) algorithm by brute force requires time equal to roughly 2n/2 invocations of the underlying cryptographic algorithm, compared with roughly 2n in the classical case,[15] meaning that symmetric key lengths are effectively halved: AES-256 would have the same security against an attack using Grover's algorithm that AES-128 has against classical brute-force search (see Key size).

Quantum cryptography could potentially fulfill some of the functions of public key cryptography. Quantum-based cryptographic systems could, therefore, be more secure than traditional systems against quantum hacking.[16]

Besides factorization and discrete logarithms, quantum algorithms offering a more than polynomial speedup over the best known classical algorithm have been found for several problems,[17] including the simulation of quantum physical processes from chemistry and solid state physics, the approximation of Jones polynomials, and solving Pell's equation. No mathematical proof has been found that shows that an equally fast classical algorithm cannot be discovered, although this is considered unlikely.[18] However, quantum computers offer polynomial speedup for some problems. The most well-known example of this is quantum database search, which can be solved by Grover's algorithm using quadratically fewer queries to the database than that are required by classical algorithms. In this case, the advantage is not only provable but also optimal, it has been shown that Grover's algorithm gives the maximal possible probability of finding the desired element for any number of oracle lookups. Several other examples of provable quantum speedups for query problems have subsequently been discovered, such as for finding collisions in two-to-one functions and evaluating NAND trees.

Problems that can be addressed with Grover's algorithm have the following properties:

For problems with all these properties, the running time of Grover's algorithm on a quantum computer will scale as the square root of the number of inputs (or elements in the database), as opposed to the linear scaling of classical algorithms. A general class of problems to which Grover's algorithm can be applied[19] is Boolean satisfiability problem. In this instance, the database through which the algorithm is iterating is that of all possible answers. An example (and possible) application of this is a password cracker that attempts to guess the password or secret key for an encrypted file or system. Symmetric ciphers such as Triple DES and AES are particularly vulnerable to this kind of attack.[citation needed] This application of quantum computing is a major interest of government agencies.[20]

Since chemistry and nanotechnology rely on understanding quantum systems, and such systems are impossible to simulate in an efficient manner classically, many believe quantum simulation will be one of the most important applications of quantum computing.[21] Quantum simulation could also be used to simulate the behavior of atoms and particles at unusual conditions such as the reactions inside a collider.[22]

Quantum annealing or Adiabatic quantum computation relies on the adiabatic theorem to undertake calculations. A system is placed in the ground state for a simple Hamiltonian, which is slowly evolved to a more complicated Hamiltonian whose ground state represents the solution to the problem in question. The adiabatic theorem states that if the evolution is slow enough the system will stay in its ground state at all times through the process.

The Quantum algorithm for linear systems of equations or "HHL Algorithm", named after its discoverers Harrow, Hassidim, and Lloyd, is expected to provide speedup over classical counterparts.[23]

John Preskill has introduced the term quantum supremacy to refer to the hypothetical speedup advantage that a quantum computer would have over a classical computer in a certain field.[24] Google announced in 2017 that it expected to achieve quantum supremacy by the end of the year though that did not happen. IBM said in 2018 that the best classical computers will be beaten on some practical task within about five years and views the quantum supremacy test only as a potential future benchmark.[25] Although skeptics like Gil Kalai doubt that quantum supremacy will ever be achieved,[26][27] in October 2019, a Sycamore processor created in conjunction with Google AI Quantum was reported to have achieved quantum supremacy,[28] with calculations more than 3,000,000 times as fast as those of Summit, generally considered the world's fastest computer.[29] Bill Unruh doubted the practicality of quantum computers in a paper published back in 1994.[30] Paul Davies argued that a 400-qubit computer would even come into conflict with the cosmological information bound implied by the holographic principle.[31]

There are a number of technical challenges in building a large-scale quantum computer,[32]. David DiVincenzo listed the following requirements for a practical quantum computer:[33]

Sourcing parts for quantum computers is very difficult: Quantum computers need Helium-3, a nuclear research byproduct, and special cables that are only made by a single company in Japan.[34]

One of the greatest challenges is controlling or removing quantum decoherence. This usually means isolating the system from its environment as interactions with the external world cause the system to decohere. However, other sources of decoherence also exist. Examples include the quantum gates, and the lattice vibrations and background thermonuclear spin of the physical system used to implement the qubits. Decoherence is irreversible, as it is effectively non-unitary, and is usually something that should be highly controlled, if not avoided. Decoherence times for candidate systems in particular, the transverse relaxation time T2 (for NMR and MRI technology, also called the dephasing time), typically range between nanoseconds and seconds at low temperature.[35] Currently, some quantum computers require their qubits to be cooled to 20 millikelvins in order to prevent significant decoherence.[36]

As a result, time-consuming tasks may render some quantum algorithms inoperable, as maintaining the state of qubits for a long enough duration will eventually corrupt the superpositions.[37]

These issues are more difficult for optical approaches as the timescales are orders of magnitude shorter and an often-cited approach to overcoming them is optical pulse shaping. Error rates are typically proportional to the ratio of operating time to decoherence time, hence any operation must be completed much more quickly than the decoherence time.

As described in the Quantum threshold theorem, if the error rate is small enough, it is thought to be possible to use quantum error correction to suppress errors and decoherence. This allows the total calculation time to be longer than the decoherence time if the error correction scheme can correct errors faster than decoherence introduces them. An often cited figure for the required error rate in each gate for fault-tolerant computation is 103, assuming the noise is depolarizing.

Meeting this scalability condition is possible for a wide range of systems. However, the use of error correction brings with it the cost of a greatly increased number of required qubits. The number required to factor integers using Shor's algorithm is still polynomial, and thought to be between L and L2, where L is the number of qubits in the number to be factored; error correction algorithms would inflate this figure by an additional factor of L. For a 1000-bit number, this implies a need for about 104 bits without error correction.[38] With error correction, the figure would rise to about 107 bits. Computation time is about L2 or about 107 steps and at 1MHz, about 10 seconds.

A very different approach to the stability-decoherence problem is to create a topological quantum computer with anyons, quasi-particles used as threads and relying on braid theory to form stable logic gates.[39][40]

Physicist Mikhail Dyakonov has expressed skepticism of quantum computing as follows:

There are a number of quantum computing models, distinguished by the basic elements in which the computation is decomposed. The four main models of practical importance are:

The quantum Turing machine is theoretically important but the direct implementation of this model is not pursued. All four models of computation have been shown to be equivalent; each can simulate the other with no more than polynomial overhead.

For physically implementing a quantum computer, many different candidates are being pursued, among them (distinguished by the physical system used to realize the qubits):

A large number of candidates demonstrates that the topic, in spite of rapid progress, is still in its infancy. There is also a vast amount of flexibility.

The class of problems that can be efficiently solved by quantum computers is called BQP, for "bounded error, quantum, polynomial time". Quantum computers only run probabilistic algorithms, so BQP on quantum computers is the counterpart of BPP ("bounded error, probabilistic, polynomial time") on classical computers. It is defined as the set of problems solvable with a polynomial-time algorithm, whose probability of error is bounded away from one half.[61] A quantum computer is said to "solve" a problem if, for every instance, its answer will be right with high probability. If that solution runs in polynomial time, then that problem is in BQP.

BQP is contained in the complexity class #P (or more precisely in the associated class of decision problems P#P),[62] which is a subclass of PSPACE.

BQP is suspected to be disjoint from NP-complete and a strict superset of P, but that is not known. Both integer factorization and discrete log are in BQP. Both of these problems are NP problems suspected to be outside BPP, and hence outside P. Both are suspected to not be NP-complete. There is a common misconception that quantum computers can solve NP-complete problems in polynomial time. That is not known to be true, and is generally suspected to be false.[62]

The capacity of a quantum computer to accelerate classical algorithms has rigid limitsupper bounds of quantum computation's complexity. The overwhelming part of classical calculations cannot be accelerated on a quantum computer.[63] A similar fact prevails for particular computational tasks, like the search problem, for which Grover's algorithm is optimal.[64]

Bohmian Mechanics is a non-local hidden variable interpretation of quantum mechanics. It has been shown that a non-local hidden variable quantum computer could implement a search of an N-item database at most in O ( N 3 ) {displaystyle O({sqrt[{3}]{N}})} steps. This is slightly faster than the O ( N ) {displaystyle O({sqrt {N}})} steps taken by Grover's algorithm. Neither search method will allow quantum computers to solve NP-Complete problems in polynomial time.[65]

Although quantum computers may be faster than classical computers for some problem types, those described above cannot solve any problem that classical computers cannot already solve. A Turing machine can simulate these quantum computers, so such a quantum computer could never solve an undecidable problem like the halting problem. The existence of "standard" quantum computers does not disprove the ChurchTuring thesis.[66] It has been speculated that theories of quantum gravity, such as M-theory or loop quantum gravity, may allow even faster computers to be built. Currently, defining computation in such theories is an open problem due to the problem of time, i.e., there currently exists no obvious way to describe what it means for an observer to submit input to a computer and later receive output.[67][68]

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