Weekly | set new highs in qubits and fidelity; the Heisenberg limit can be reached without quantum entanglement
Headlines This Week
Implementation of 512 qubits in neutral atomic system
In a recent study, Hannes bernien's team at the University of Chicago implemented a two-element atomic array that can independently control a single rubidium atom and cesium atom. The researchers used 512 optical tweezers to capture 256 rubidium and 256 cesium atoms, and observed that the crosstalk between the two elements was negligible. Thus, the neutral atom system achieved a record 512 qubits. The paper has been published in Physical Review X.
The quantum architecture based on neutral atom array can break through the current limitations on system scale, coherence and high fidelity state preparation and control. The hybrid nature of this atomic array also opens the door to many applications that are impossible for a single kind of atoms. Because the two substances are independently controllable, the atoms of one element can be used as quantum memory, while the other element can be used for quantum computing, playing the roles of ram and CPU on the computer respectively.
Link:
https://journals.aps.org/prx/abstract/10.1103/PhysRevX.12.011040
Quantum set a spam fidelity record of 99.9904%
Ionq announced that the readout fidelity of its new barium based quantum computer, that is, the fidelity of state preparation and measurement (spam), has increased from 99.5% to 99.96%.Quantum set a spam fidelity record of 99.9904%.
Coincidentally, the ion trap system of quantum, a subsidiary of Honeywell, uses barium ion qubits to improve the fidelity of spam to 99.9904% - the highest of all quantum technologies so far.
Quantum researchers believe that the spam fidelity needs to reach 99.97% to 99.99% to reach the level that the logical error rate exceeds the main physical error rate.
Link:
https://mp.weixin.qq.com/s/aXqZqB1GZC15r4KB4kqcMg
Scientists reached the Heisenberg limit without using quantum entanglement
Recently, a South Korean research team proposed a method to achieve quantum metrology accuracy without using entanglement resources. The research team led by Professor Yoon ho Kim and Dr yosep Kim of the Department of physics of POSCO University of science and technology found a weak value amplification (WVA) method to reach the Heisenberg limit without quantum entanglement. Heisenberg limit refers to the precision that can be finally achieved in quantum metrology. The study was recently published in the international academic journal Physical Review Letters.
Researchers have confirmed that in weak value amplification, the Heisenberg limit is reached without entanglement through the iterative interaction between different quantum states. They explained that this is caused by the local iterative interaction between each particle of the entangled system and the instrument, not by the quantum entanglement itself. "This study will contribute to the practical application of quantum metrology by verifying that entanglement is not an absolute requirement to reach the Heisenberg limit," said the professor who led the study.
Link:
https://www.eurekalert.org/news-releases/945253
Caixabank became the first bank in the world to apply quantum computing to portfolio hedging calculation in the insurance industry
Caixabank, Spain's leading financial group, and d-wave systems, a quantum computing company, announced the business results of two important financial quantum hybrid computing applications, including portfolio optimization and investment hedge computing. Due to their collaboration, quantum hybrid applications significantly reduce the computing time to solve complex financial problems, improve portfolio optimization, improve the internal rate of return (IRR) of bond portfolio, and minimize the capital required for hedging operations.
Compared with traditional solutions, the computing time is reduced by up to 90%. This reduction in computing time helps to increase the complexity of modeling, allowing more dynamic models to better adapt to the real-time market; Optimize investment capital while maintaining a constant risk level; Improve the hedging decision-making process. In terms of portfolio selection and allocation, the algorithm can quickly generate a portfolio that can be optimized for more constraints in a shorter time. The result is a successful application that increases the internal rate of return by 10% in the selected bond portfolio.
Link:
Denmark's largest bank tests continuous variable QKD Technology
The Danish Technical University, in cooperation with dansk bank and KPMG, Denmark's largest banks, successfully transmitted data between the bank's two analog data center computers using continuous variable quantum key distribution (QKD) technology. The event marks the first time that Nordic countries have used quantum keys to protect data transmission on networks outside the laboratory. This may be of great significance to future security. Banks have the responsibility to constantly seek new ways to protect customer data and ensure that they are ahead of criminals in the arms race in science and technology.
Link:
https://www.finextra.com/newsarticle/39774/danske-bank-tests-quantum-communication-for-data-transfer
By 2027, the global quantum technology market will reach US $42.4 billion
Research and markets, a market consulting agency, released the report "quantum technology market in computing, communication, imaging, security, sensing, modeling and simulation from 2022 to 2027". The report concludes as follows:
● by 2027, the global overall quantum technology market will reach US $42.4 billion
● by 2027, quantum computing will lead the market with us $16.1 billion and a compound annual growth rate of 39.4%
● North America will become the largest regional market for overall quantum technology
● by 2027, China will lead the quantum technology market in the Asia Pacific region with a compound annual growth rate of 38.5%, reaching US $5.41 billion
● by 2027, Germany will lead the European quantum technology market with a compound annual growth rate of 33.1%, reaching US $3.6 billion
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National Strategy
NATO successfully tested anti quantum security network
With the escalation of geopolitical tensions, NATO attaches great importance to network security. Since March last year, the NATO Network Security Center (NCSC) has used the virtual private network (VPN) provided by the British company post quantum to test and run the secure communication flow, and said that it is a secure network that can resist quantum computer attacks. Now, NATO has announced the completion of the test.
Link:
https://mp.weixin.qq.com/s/4hawZrd1izwVe8Z7cnhmww
Zu Chongzhi was selected as one of the top ten scientific advances in China in 2021
Zu Chongzhi was selected as one of the top ten scientific advances in China in 2021. The selection of the 17th "top ten advances in Chinese science" was led by the high technology research and Development Center (basic research management center) of the Ministry of science and technology. Five editorial departments including China basic science, science and technology guide, Journal of the Chinese Academy of Sciences, China Science Foundation and Science Bulletin participated in recommending scientific research progress, and invited academicians of the Chinese Academy of Sciences More than 3500 well-known experts and scholars, including academicians of the Chinese Academy of engineering, directors of state key laboratories, members of the overall expert group and project leaders of key projects related to national key R & D plans, experts of the original 973 Plan Advisory Group and advisory group and chief scientists of the project, voted online on 30 candidate scientific developments, The top 10 winners were selected into the "top ten advances in Chinese Science in 2021".
Link:
https://mp.weixin.qq.com/s/WVNeMIO11KvqKBQYAagJdw
Us quantum economic development alliance welcomes the first international member
Oxford Instruments announced that it has become a full member of the American quantum Economic Development Alliance (qed-c). This is the first international member of qed-c. The mission of the alliance is to support and develop a strong commercial quantum industry and related supply chains. Qed-c is managed by Sri international and established with the support of the National Institute of standards and technology of the U.S. Department of Commerce. It is part of the U.S. government's strategy to promote quantum information science. Today, it has more than 200 members, including more than 150 companies.
Link:
https://www.oxinst.com/news/oxford-instruments-announces-its-membership-of-qed-c
NSF funded $440000 to the State University of New York Institute of technology for next-generation quantum research
As part of an interagency collaborative research team led by the Institute of optics at the University of Rochester, Spyridon Galis received $440000 from the National Science Foundation (NSF), which focuses on processing quantum information carried by photons. Galis is an associate professor at the school of nanoscience and engineering at the State University of New York Institute of technology. He will guide graduate and undergraduate students to complete the work. With a total value of 2.5 million US dollars, the four-year research work aims to explore and develop a multifunctional integrated quantum photonic processor. The processor will be able to obtain information from photons and transmit it efficiently and accurately between different systems.
Link:
https://altamontenterprise.com/03032022/suny-poly-professor-gets-440k-nsf-next-gen-quantum-research
Australia launches quantum education and research program
The Pawsey supercomputing research center in Western Australia announced that it is supporting a groundbreaking quantum education and research program to enable students to use Australia's first teaching quantum computers.
The quantum education and Research Center will be located at the University of Western Australia (UWA). The new program will enable researchers and students to improve in emerging areas of quantum computing and cooperate with Pawsey's quantum supercomputing innovation center. The center will be led by UWA quantum physicist Professor Jingbo Wang, and will provide two desktop quantum computers running at room temperature - the 2-qubit spinq Gemini and 3-Qubit spinq triangle systems of Shenzhen quantum spin technology Co., Ltd.
Link:
https://mp.weixin.qq.com/s/hOYChmrXpZTNODv8d5zMrA
The Canadian Institute for Quantum Algorithms has teamed up with Xanadu to create Canada's highly skilled quantum workforce
The Canadian Institute for Quantum Algorithms (QAI), a nonprofit organization that fosters collaboration between industry, academia and government in British Columbia (BC), has partnered with Toronto-based optical quantum computing company Xanadu to build a highly skilled workforce of the future that will drive economic growth in B.C. and across the country.
One aspect of QAI's mission is to develop a robust talent pipeline for quantum information science, and students will leverage Xanadu's hardware, software, and expertise in quantum computing to accelerate the process. Students will benefit from Xanadu's open source software library PennyLane to learn how to write quantum computing algorithms. As part of the training materials and courses developed by Xanadu and QAI, students will be able to work with QAI's industry and government partners in B.C. to solve real-world problems, providing students with a unique experience and a real-world perspective on quantum computing.
Link:
https://www.azoquantum.com/News.aspx?newsID=8823
Business Dynamics
Quantum computing company Rigetti went public on March 2
On March 2, Rigetti's stock was officially traded on nasdaq capital markets under the ticker symbol "RGTI". The stock underperformed in the three days before the listing, falling from $11.368 to the current $7.45. Rigetti went public through a merger with special-purpose acquisition company Supernova, a deal that brought it $261.75 million in revenue, primarily to accelerate the development of its multi-generation quantum processors.
Link:
https://mp.weixin.qq.com/s/vtHfcNORmrjXVKOkmk5mRA
less than a year after its establishment, turing quantum completed the third round of financing, accumulating more than 500 million yuan
Turing Quantum, the first optical quantum computing company in China, announced the completion of the third round of Pre-A+ financing on February 28 after completing a multi-hundreds of millions of yuan Pre-A round of financing. The funds raised will be mainly used to create an application ecology for optical quantum computing and intelligent industrialization. So far, Turing Quantum, which has been established for less than a year, has completed three rounds of large financing, with a cumulative financing amount of more than 500 million yuan.
Turing quantum has completed the process from laboratory to industrialization and formed a complete market-oriented product system. It has achieved international leading technological advantages in light quantum chip, special light quantum computer, light quantum measurement and control system, light quantum EDA software and quantum cloud platform.
Link:
https://mp.weixin.qq.com/s/ixbvlBMBp0M_UvRNiKysLA
quantum products are unveiled at mobile world congress 2022
MWC Mobile World Congress 2022 is taking place in Barcelona, Spain, under the theme "Connectivity Unleashed Unleashes Endless Possibilities".
It is noteworthy that quantum technology has become one of the focuses of this conference. Not only will many forums be held, but also many quantum technology companies have unveiled their products. The conference held three cutting-edge technology forums, namely cutting-edge materials, technology behind the meta universe and quantum technology. What is the game plan for quantum computing Forum.
Link:
https://mp.weixin.qq.com/s/FZpjivaB_ad7Mvh4lN0jsg
Quix introduces a new 20-mode photonic quantum processor
Dutch optical quantum computing company QuiX Quantum has announced the launch of "the world's largest optical quantum processor", and the new 20 quantum mode (qumode) processor is superior in scale and quality to the previous generation of 12 mode processors. This is a processor based on the continuous variable (CV) model. Qubits in superconducting or ion trap quantum computers are discrete variables (DV).
The Shin-optic quantum processor called Dolphin20_1550 has much lower losses than previous generation processors. The specific parameters are compared as follows:
Link:
https://mp.weixin.qq.com/s/cqOGK_toujOTCxexXTFCLw
Siloton received investment aiming to use quantum to improve eye health
Quantum Exponential, a company focused on investing in quantum technology, announced in a statement that it had invested around £300,000 as part of a around £470,000 seed round from Siloton, a technology company that uses quantum technology and photonic integrated circuits for subsurface optical scanning devices in the healthcare and nondestructive testing sectors.
According to the statement, this is Quantum Exponential's first equity investment in quantum technology since its listing in November 2021.
This is an investment in disruptive health technology companies that leverage quantum technology. Siloton has created a new generation of devices using quantum calibration technology to monitor the disease status of age-related macular degeneration patients.
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Montana instruments is about to release a new low-temperature nanotambler
Montana Instruments announced the upcoming release of its new cryogenic nanolocator The Rook™ in the spring of 2022. The Rook™ has the lowest triaxial vibration to keep the sample in focus. Features include:
● three-axis design for optimal sample temperature and motion control
● low vibration
● robust and reliable design
● fully integrated plug-and-play control
● Galaxy software control, remote monitoring, and scripting
● first-class temperature controlled fuse
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Doge Protocol releases quantum-resistant blockchain test network
The Doge Protocol announced that this month it released the first test network equipped with quantum encryption resistance. The network is powered by state-of-the-art anti-quantum encryption technology to protect user accounts and inter-node communications from quantum computer threats. The Doge Protocol also introduced a block explorer that can be used to view transactions, blocks, and account balances. The Doge Protocol is a quantum-resistant blockchain that uses PoS (Proof of Stake) consensus. The entire project is open and decentralized, so anyone can contribute to the project.
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Rigetti Computing announces Michael Harburn as Chief Technology Officer
Quantum computing company Rigetti Computing corporation announced the appointment of Michael Harburn, senior vice president of manufacturing operations and QPU engineering at Rigetti, as chief technology officer, who will continue to oversee and lead the development of next-generation quantum computers.
Michael Harburn has over 25 years of experience in the semiconductor, MEMS and OLED industries, having previously led teams in operations, manufacturing and R&D engineering. Harburn previously served as Kateeva's vice president of global operations and previously served as Senior Development and NPI Director for FormFactor.
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The IEEE Quantum Quantum Computing Climate Change Summit was held on March 2
IEEE Quantum, a leading community for quantum computing conferences, research, and educational programs, hosted the Quantum Computing Climate Change Summit on March 2. The leader and chair of the climate action initiative is Maëva Ghonda, a sustainability expert and chair of the Quantum Computing Climate Change Advisory Committee.
Following Maëva Ghonda's opening remarks, the Quantum Computing Climate Change Summit had a presentation and roundtable discussion. Tackling climate change is one of the most important issues for humanity, and quantum computing promises to change the way we produce and store large amounts of affordable renewable energy, which will help solve many environmental problems.
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QC Ware appointed Christoph Siegert as Head of Product to expand the Quantum-as-a-Service Platform
QC Ware, a leading developer of quantum algorithms running on recent quantum computing hardware, announced the appointment of Christoph Siegert as the company's new head of product, leading the company's global software strategy and development. Focus on leading product teams to achieve rapid growth and product market adaptation to cloud and emerging technologies. Prior to joining QC Ware, he was a Senior Director at Microsoft, where he led Azure Engineering's global expansion into new cloud regions.
Siegert joined QC Ware during a period of rapid growth for the company and industry. IDC predicts that customer spending on quantum computing will grow from $412 million in 2020 to $8.6 billion in 2027.
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Expand quantum computing business, guodun quantum's revenue increased by 34% in 2021
On february 26, guodun quantum (stock code: 688027) released its 2021 annual performance report. during the reporting period, the company actively coordinated the layout of the quantum information industry, with quantum communication as the core, and continuously expanded scientific research instrument products such as quantum computing, achieving operating income of 179 million yuan, an increase of 33.55% over the same period of the previous year.
Link：
https://mp.weixin.qq.com/s/E-VbdiRfayKKv9AzHlPEyQ
amazon's quantum computing cloud service provides access to the first european system
Oxford Quantum Circuits OQC, Europe's leading quantum computing-as-a-service company, announced on Feb. 28 that it debuted its latest system, Lucy, a superconducting quantum computer with 8 qubits, on Amazon's Braket quantum computing cloud service. The system provides an advantage for onshore and nearshore data in Europe, which is a major concern for European government agencies as well as large companies with data residency and sovereignty requirements. These organizations can now access quantum processors in Europe through OQC and Amazon Braket.
Link：
https://oxfordquantumcircuits.com/oqc-first-european-quantum-on-braket
China's first cold atom quantum company received tens of millions of yuan in financing
Recently, Zhongke KuYuan Technology (Wuhan) Co., Ltd., a developer of cold atom quantum precision measurement and quantum computing technology, completed a round of financing of tens of millions of yuan, and the exclusive investor is Zhongke Chuangxing. It is reported that this round of financing is mainly used for the R & D and industrialization of quantum precision measurement instruments and atomic quantum computing, further strengthen the company's talent reserve, enhance the company's core competitiveness, and promote and apply a series of quantum precision measurement instruments and quantum computing products in the fields of scientific research, teaching and popular science.
Founded in 2020, the core team originated from the institute of precision measurement innovation and technology of the chinese academy of sciences, the company received the investment in the seed round of the zhongke keyuan fund in 2020, and was selected as a key enterprise in the quantum technology industry in wuhan; the atomic absolute gravity meter developed by the core team participated in the international comparison of the tenth absolute gravity meter, the measurement results were recognized by the international bureau of metrology, and the key indicators such as instrument measurement sensitivity and stability have reached the international first-class level. the miniaturized atomic gravimeter independently developed by the team was selected into the list of "independently developed instrument products of the chinese academy of sciences".
Link:
https://mp.weixin.qq.com/s/sluwuHGEzWX8V5tPA9OHXA
Intellectual property corporation of canada announces patent services for quantum technologies
Canadian intellectual property (IP) firm Bereskin & Parr announced that it will provide legal, patent and trademark services to companies developing or improving quantum computers, quantum sensors and other quantum technologies. The company already has existing clients in the field and will "pool" this expertise and experience to provide clients with the best professionals to meet their needs.
The company expects the quantum field to grow rapidly, with governments and businesses focusing more on quantum technologies in both research and development and investment.
Link:
https://thequantuminsider.com/2022/02/28/canadian-ip-firm-opens-quantum-technologies-practice/
Science and technology progress
quantum computers have fabricated the largest time crystal to date
Last year, the Google team announced the first use of a quantum computer to create a "time crystal." Now, Philipp Frey and Stephan Rachel of the University of Melbourne's School of Physics have used IBM's quantum computer to fabricate the largest time crystal to date. A time crystal is a system of quantum particles that is locked in a permanent loop in time, somewhat similar to the repetitive spatial pattern of ordinary crystals in the original.
The new time crystal is made up of 57 quantum particles, more than double the 20-particle time crystal that Google scientists simulated last year. Chetan Nayak, a Microsoft condensed matter physicist who wasn't involved in the work, said the system was so big that conventional computers couldn't simulate it. "So it's definitely an important step forward." This work demonstrates the ability of quantum computers to simulate complex systems that might otherwise exist only in physicists' theories.
Link:
https://mp.weixin.qq.com/s/mHg1wcvGhDw2n_E5YkpkzQ
the 2021 mozi quantum prize was awarded for superconducting quantum research
On March 2, the 2021 Mozi Quantum Award was announced. This year's prize area is to observe quantum effects in superconducting devices. There were three winners: John Clarke of the University of California, Berkeley; Michel H. Devoret of Yale University; and Yasunobu Nakamura of the Riken Institute of Science and Chemistry in Japan.
The award was won for "leading position in creating superconducting quantum circuits and qubits". each winner will receive 1.25 million yuan (about $150,000 after tax) in cash and a medal of honor sponsored by the mozi quantum foundation.
To date, the mozi quantum prize has been awarded four times to recognize international scientists who have made outstanding contributions in the fields of quantum communication, quantum simulation, quantum computing and quantum precision measurement.
Link:
http://www.miciusprize.org/index/lists/003004
Tsinghua university realizes quantum memory-enhanced non-local map preparation
Recently, the Duan Luming Research Group of the Institute for Interdisciplinary Information Sciences of Tsinghua University has made important progress in the field of quantum information, using quantum memory for the first time to efficiently prepare non-local maps in experiments, demonstrating the application prospect of quantum memory for quantum information processing and quantum measurement in large-scale distributed systems. The result's research paper, Quantum-Memory-Enhanced Preparation of Nonlocal Graph states, was recently published in the international academic journal Physical Review Letters.
The results show that the four photon GHZ state generated in this way changes the complexity of large-scale preparation efficiency. When n pairs of entangled pairs need to be connected in the future, the preparation efficiency will rise from the exponential attenuation level to the polynomial level, which shows the superiority of quantum storage scheme in preparing large-scale graph states. In addition, the researchers further verified the mabk inequality by using the prepared four photon GHZ state, and demonstrated the quantum secret key distribution protocol in quantum cryptography. This work has realized an efficient prototype for preparing large-scale graph States, which has taken an important step for its various applications in quantum information science and quantum metrology.
Link:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.080501
Scientists implement quantum repeaters based on trapped ions
To create a large-scale quantum computer network, researchers need to develop devices that can amplify and enhance network signals. these devices, called quantum repeaters, are responsible for allocating entangled resources on the network.
Now, Prajit Dhara of the University of Arizona and colleagues have studied how multiplexing techniques affect end-to-end entanglement rates in a network of quantum repeaters composed of trapped ions. The researchers say their research helps pave the way for the realization of ion-trapping quantum repeaters in quantum networks.
Link:
https://physics.aps.org/articles/v15/s29
Dutch researchers have developed more powerful light quantum processors
If you want to use light for quantum computing, the photons emitted by the light source must be as similar as possible, and if they are not the same, typical quantum properties such as entanglement and superposition cannot be detected. for example, if the color of one photon is slightly different from the color of another photon, there is a risk that quantum properties will not appear and that calculations cannot be performed.
Now, the University of Twente in the Netherlands has developed more powerful optical quantum processors. The study proposes a three-photon source based on titanium phosphate (KTP), which, in its current version, can be upgraded to 11 identical photons. The processor is a system with 12 inputs and 12 outputs. In between, there is a system of light guide channels made of silicon nitride with extremely low losses. The first processor of this type has 8 inputs and 8 outputs.
Link:
https://phys.org/news/2022-02-photons-quantum-processor.html
IBM has developed a new superconducting switching device
IBM has developed a new superconducting switching device that may prove useful for both classical and quantum computers in the next generation of components. In the latest paper, scientists explain how the relatively small number of these high-energy electrons is enough to destroy the superconducting state in nanowires. A new device geometry is realized in which the current of high-energy electrons is generated without exposing nanowires to electric field or leakage current. Instead, the current is generated near the nanowires through an additional gate.
A new strategy is proposed to reduce the negative effect of Phonons on the coherence of superconducting qubits. One way to avoid the harmful effects of phonons may be to reduce or limit the effects of emitted phonons by constructing a substrate.
Link:
https://research.ibm.com/blog/vibrations-could-flip-the-switch-on-future-superconducting-devices
Symmetrical selection coupling of superconducting quantum emitters and microwave waveguides
Recently, researchers at chalmers institute of technology used a new structure to couple two modes of quantum emitters and two waveguides, respectively. in applications such as nonlinear quantum optics and quantum communication, it is sometimes necessary to manipulate the coupling between a quantum emitter composed of qubits and the environment. this work uses symmetry to achieve selective coupling, avoiding the frequency modulation or phase modulation difference usually required for coupling, reflecting that good structural design can reduce the complexity of measurement and control, and providing a new idea for the complex coupling between quantum devices.
The quantum emitter is two capacitively coupled transmon qubits, strongly coupled to give two modes of symmetry (s) and antisymthetic (a). Each transmon has two capacitive pads, one waveguide coupled to two pads corresponding to the inter-bit coupling capacitance, and the other waveguide is coupled to a bit of coupling capacitance pad and another bit away from the coupling capacitor pad, respectively, thus achieving coupling to symmetric and antisymmetric modes, respectively. They also demonstrated two applications, one is through the two-photon Raman process, where the s mode and a mode can be coherently coupled, thus achieving the function of frequency conversion with an efficiency close to 1. The other is that the s mode and the a mode can also be entangled with the ground state respectively, and then emit photons to the two waveguides through spontaneous radiation, so as to achieve entanglement between the photons propagated in the two waveguides.
Link:
https://arxiv.org/abs/2202.12209
Tsinghua university has realized the generation and manipulation of polarization entangled bell states on silicon light quantum chips
Recently, the latest research result of Zhang Wei's team at Tsinghua University, "Generation and dynamic manipulation of frequency degenerate polarization entangled Bell states by a silicon quantum photonic circuit", was published in chip, a global cutting-edge comprehensive research journal. The first author is doctoral student Liu Dongning. The research results have realized the generation and manipulation of polarization entangled Bell states on silicon light quantum chips.
Researchers said that the output quantum state can be dynamically manipulated, which will stimulate new applications of silicon optical quantum chips. In the work, the BSM experiment is used to demonstrate the transient process of the dynamic longitudinal adjustment of the quantum state by the thermal phase shifter on the chip. The results show that the output quantum state can be switched and the modulation rate can reach 10 kHz. The function of quantum state dynamic manipulation can be applied to quantum information coding based on Bell state, which has important prospects in quantum communication and optical quantum information processing. It can be predicted that the on-chip dynamic manipulation of quantum states will attract more and more attention and become a new entry point for the research and application of light quantum chips.
Link:
https://mp.weixin.qq.com/s/4P3fLZH1RWnbOTUeUyy34Q
Quantum teleportation using a classical bit
Quantum teleportation allows people to use a pair of (pre shared) entangled qubits and classical information bits to transmit arbitrary qubits from point a to point B. Traditional teleportation protocols use two bits of classical information and assume that the sender can only access one copy of any quantum bit to be transmitted. If the sender can access multiple copies of the qubit to be transmitted, can it do better than two bits of classical information without limiting the state of the qubit?
So researchers at the University of Nebraska-Omaha have proposed an improved quantum teleportation protocol that allows sender Alice to reset the state of an entangled pair to its initial state using only local operations. Therefore, the proposed teleportation protocol only needs to transmit a classical bit with a probability greater than half. This has important implications for efficient quantum communication and the security of quantum encryption protocols based on quantum entanglement.
Link:
https://www.nature.com/articles/s41598-022-06853-w
The institute of fine testing of the chinese academy of sciences uses quantum simulation technology to confirm that the real quantum system has a limit to the speed of manipulation
Recently, the research team of the Institute of Precision Measurement cooperated with the external units to design and experimentally demonstrate a controllable quantum non-equilibrium thermodynamic process using a quantum simulation experimental platform constructed by ultra-cold 40Ca+ ions, and for the first time at the single atomic level, the new quantum thermodynamic properties of "the control speed of the quantum system far from the equilibrium state is subject to the entropy generation rate of the system" were verified with high precision, and the research results were published in the top journal of physics, Physical Review Letters.
The research work helps to understand the speed limits of real quantum manipulation, further optimize quantum technologies involving non-equilibrium thermodynamic processes such as quantum measurement, manipulation and quantum information reading, and once again demonstrate the unexpected role of thermodynamics in real quantum processes. in particular, the work demonstrates that a quantum simulator composed of a single ion can accurately and credibly model quantum non-equilibrium thermodynamic processes that are difficult to realistically observe, once again demonstrating the great potential of quantum technology and the future prospects of a disruptive technology.
Link:
http://apm.cas.cn/kydt/202202/t20220222_6370788.html
Nanjing university has made important progress in the field of on-chip integrated optical non-reciprocity
In collaboration with external professors, the professorial research group of the School of Modern Engineering of Nanjing University published the latest research results on integrated optical non-mutually easy devices under the title of "Quantum Squeezing Induced Optical Nonreciprocity" in the authoritative journal of physics "Physical Review Letters" on February 23, 2022. The study of non-reciprocity not only has basic scientific significance, but also has wide application value, opening up a new way to realize the integration of non-reciprocal quantum information processing.
Xia Keyu's research group and international collaborators put forward on-chip integrated all-optical control optical isolation method and non reciprocal photonic transistor. This achievement creatively puts forward a theoretical scheme of inducing optical non reciprocity by using unidirectional compressed cavity mode. As shown in the figure, see the paper for details. The proposed scheme can realize the non reciprocal photonic transistor with control gain G greater than 1. The all-optical controlled optical nonreciprocal device reported in this work adopts lithium niobate optical microcavity with simple structure, which can be used for nonreciprocal regulation of classical coherent light and single photon.
Link:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.083604
Scientists successfully measured the non-markovity of multichannel quantum open dynamics
Recently, the research team of Professor Long Guilu of the Department of Physics of Tsinghua University, the Beijing Institute of Quantum Information Science and the research team of Associate Professor Ai Qing of the Department of Physics of Beijing Normal University cooperated to tune the system and environmental parameters using the newly developed accurate and efficient method on a controllable nuclear magnetic resonance experimental platform, and by tuning the fundamental frequency, it proved that quantum mutual information combined with quantum Fisher information can measure the non-Markovity of multi-channel quantum open dynamics, providing a new idea for better studying the dynamics of open systems. On March 3, 2022, the research was published in the journal npj Quantum Information of Nature Publishing Group under the title Global Correlation and Local Information Flows in Controllable Non-Markovian Open Quantum Dynamics.
Link:
https://mp.weixin.qq.com/s/rR4Hr18sFBkT2aqVWlpHkg
