Nav: Home

A convex-optimization-based quantum process tomography method for reconstructing quantum channels

February 10, 2020

Quantum process tomography is often used to completely characterize an unknown quantum process. However, it may lead to an unphysical process matrix, which will cause the loss of information with respect to the tomography result. Professor Xian-Min Jin and his group from Center for Quantum Information Technologies in Shanghai Jiao Tong University (SJTU) reported a new quantum process tomography method which is based on convex optimization. They demonstrated that this new method is able to minimize the errors between the process matrix and the experimental results effectively and works well both in unitary and non-unitary quantum channels. This work was published in Science Bulletin.

As for a general quantum channel, it might include a series of non-unitary operations. However, previous researches mainly focus on the unitary and near-unitary operations while there are few studies on the non-unitary operations.

Professor Jin chose the seawater channel as a benchmark to test their method. The seawater channel is one of the key channels for global quantum communication, which can serve as a typical representation for the general quantum channel. Their method revealed the true action of the seawater quantum channel more accurately and could well maintain the physical properties. They further tested it on the seven fundamental gates, showing that this new method can reveal the quantum channel more precisely and robustly without preliminary parameter adjustments. In addition, they prepared a series of non-unitary quantum channel. Compared with previous tomography methods, they still can reach up to 99.5% accuracy in this scenario.

Because each element of the process matrix represents different operations, it is necessary to determine each value precisely if we want to reveal the true action of the quantum channel. The work from Professor Xian-Min Jin and his group offers a more universal tool for further analyses on the general quantum channels.
See the article:

Xuan-Lun Huang, Jun Gao, Zhi-Qiang Jiao, Zeng-Quan Yan, Zhe-Yong Zhang, Dan-Yang Chen, Xi Zhang, Ling Ji, Xian-MinJin. Reconstruction of quantum channel via convex optimization. Science Bulletin, 2020, 65(4):286-292. doi: 10.1016/j.scib.2019.11.009

Science China Press

Related Work Articles:

Can't concentrate at work? This AI system knows why
Computer scientists have developed a way to measure staff comfort and concentration in flexible working spaces using artificial intelligence.
There's a better way to think about being kept waiting at work
Generally, abstract thinking leads to better outcomes, such as more creativity, wider vision and feeling more powerful.
Making light work
A collaboration between McMaster and Harvard researchers has generated a new platform in which light beams communicate with one another through solid matter, establishing the foundation to explore a new form of computing.
Does flexible work 'work' for Aussie parents?
An Australian study examining the relationship between flexibility and parent health has revealed formal family-friendly workplace provisions alone are not meeting the demands of working mothers and fathers.
Do open relationships really work?
Open relationships typically describe couples in which the partners have agreed on sexual activity with someone other than their primary romantic partner, while maintaining the couple bond.
Ebola antibodies at work
Scientists in Israel and Germany show, on the molecular level, how an experimental vaccine offers long-term protection against the disease.
Work that kills
More than 64% of employed Russians work evenings, nights or weekends, and this is one of the highest figures among European countries.
Reattaching to work is just as important as detaching from work, study finds
Employees who mentally reattach to work in the morning are more engaged at work, according to a new study.
Be yourself at work -- It's healthier and more productive
At work, it's healthier and more productive just to be yourself, according to a new study from Rice University, Texas A&M University, the University of Memphis, Xavier University, Portland State University and the University of California, Berkeley.
For many, 'flexible work boundaries' become 'work without boundaries'
Personal relationships and home life suffer for those tied to their work emails round-the-clock, according to a new study.
More Work News and Work Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Producer Tracie Hunte stumbled into a duet between Nina Simone and the sounds of protest outside her apartment. Then she discovered a performance by Nina on April 7, 1968 - three days after the assassination of Dr. Martin Luther King Jr. Tracie talks about what Nina's music, born during another time when our country was facing questions that seemed to have no answer, meant then and why it still resonates today.  Listen to Nina's brother, Samuel Waymon, talk about that April 7th concert here.