Opsin your eyes! Quantum sensors are the colour vision magicians inside our heads
In the fifth instalment of his exclusive monthly series for the South China Morning Post, American theoretical physicist and Nobel laureate Frank Wilczek explores the marvel of vision and why we can credit the quantum world for it. Read his previous articles
here
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The design of sensors that exploit the strange features of quantum mechanics is a vibrant frontier of modern physics. But nature got there first.
Some of the most impressive quantum sensors on Earth have been common for millions of years. They help us to identify objects at great distances; they warn us about unripe food, poisons and predators; they empower us to enjoy the shimmer of jewels and rainbows, or to discern small glittering gold nuggets hidden among common stones. They are the marvellous molecules at the back of our eyeballs, whose response to incoming photons gives us our colour vision.
World Quantum Day is a great moment to recognise that vision is a gift to us from the
quantum world
To appreciate why and how, it is useful to compare vision with hearing. Both are, fundamentally, ways of detecting vibrations. In
hearing , the vibrations – or sound waves – are travelling disturbances of pressure, usually in air. In vision, the vibrations are travelling disturbances in electric and magnetic fields – the class of
electromagnetic waves we call light.
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These two kinds of vibrations occur at vastly different rates. Sounds perceptible to humans are in the range of 20 to 20,000 hertz; that is, the vibrations occur 20 to 20,000 times per second. For reference, dogs hear higher frequencies too, up to 45,000Hz or so; hence the possibility of dog whistles. The electromagnetic vibrations in visible light occur roughly a trillion times faster.
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South China Morning Post
3 days ago
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Asia Times
5 days ago
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Marco Rubio's and Miles Yu's war on Chinese students is misguided
In an age of escalating geopolitical rivalry, democracy's strongest foundations — press freedom, civic trust and public accountability — are being eroded by a perfect storm of surveillance, suspicion, and systemic misinformation. This is especially visible in US-China relations, where bipartisan hawkishness has led to sweeping proposals like Senator Marco Rubio's latest effort to revoke visas from Chinese students and researchers — treating them as national security risks by default. Joining the chorus is Miles Yu, a former Chinese international student who became a top China policy adviser in the first Trump administration. In his widely cited essay, 'Enabling the Dragon,' published in November 2024 the week after Donald Trump had won the election, Yu argues that US universities have become naive enablers of the Chinese Communist Party, serving as academic outposts vulnerable to intellectual theft and ideological infiltration. Yu urges that the United States should sharply restrict academic engagement with China, calling such cooperation a national security threat. His claim is sweeping: that China has 'outsourced' its academic system to exploit American openness, and that the US must respond by severing intellectual ties. Both Rubio and Yu are also ignoring the data: Chinese nationals make up the largest share of foreign students in STEM fields — computer science, engineering, math and the physical sciences. According to the National Science Foundation, more than 80% of Chinese PhD recipients in these fields stay and work in the US after graduation, contributing directly to American innovation, entrepreneurship, and research leadership. Many have founded startups, filed patents and worked in cutting-edge labs at US universities and tech companies. The idea that they are 'outsourcing' American prosperity to China is not only false — it's self-destructive. If these students are forced out, the US will not only lose a competitive advantage in global talent — it will damage its innovation ecosystem at its roots. Immigration-driven innovation has been one of the few consistent engines of American prosperity in a polarized and gridlocked political climate. Treating every foreign-born talent as a potential spy will only drive them into the arms of competitors. Moreover, this zero-sum framing misrepresents how education actually works. American universities are not ideological weaklings — they are spaces where critical thinking, civic inquiry and pluralistic values are cultivated. Chinese students are not arriving with monolithic loyalties — they are shaped by their experiences here, often becoming some of the most perceptive critics of authoritarianism and some of the strongest defenders of democratic ideals. Diaspora students and scholars, such as the founders of China Labor Watch and Human Rights in China, have often been at the forefront of documenting abuses, challenging both Chinese state narratives and the overreach of US suspicion. They are not security liabilities — they are civic actors. And yet, they are increasingly caught in the middle. Media outlets rush to publish stories about alleged espionage long before there's due process. Federal task forces pressure universities to cut off collaborations without context. On social media, platforms like X — once Twitter — amplify xenophobic paranoia while silencing legitimate voices. The result is a digital public sphere poisoned by fear and disinformation, where nuance disappears and policy becomes a blunt instrument of exclusion. In my research — China's Emerging Inter-network Society — I explore how diaspora communities and digital platforms are reshaping political consciousness. Platforms like WeChat and TikTok are indeed double-edged: they can be used for surveillance, but also for storytelling, mutual aid, and grassroots advocacy. What Yu fails to mention is this: He was once 'the dragon' he now seeks to shut out. To presume otherwise is to vastly underestimate the power of American education — something Yu himself should know firsthand. Yet there's a glaring irony: Yu himself is living proof that American education works — not just as a system of knowledge transmission, but as a transformative force of values, perspective and civic engagement. Yu came to the US in the 1980s as an international student from China. He benefited from the very system he now decries — one that welcomed global talent, nurtured individual potential and allowed a Chinese-born scholar to rise to the highest levels of US policymaking. If America had treated him then the way he now proposes treating others, Miles Yu might still be teaching Maoist doctrine in Anhui, not advising presidents in Washington. If Miles Yu truly believed Chinese students couldn't be trusted, one wonders why he chose to stay and serve in the US government rather than return to China after pursuing his PhD degree. Doesn't his own life prove the power of American education to transform, inspire, and integrate? If we now assume every Chinese student is a CCP foot soldier, does that include him too? Or is he the exception who proves the value — not the danger — of keeping the door open? He chose to stay in the United States not because he was coerced but because the openness and meritocracy of American institutions resonated with him. If we now claim that every Chinese student is a sleeper agent for Beijing, then Yu's own journey becomes an inconvenient contradiction. Isn't he the evidence that America's democratic model can win hearts and minds? That contradiction isn't just ironic. It's emblematic of a dangerous drift in US national security thinking in which suspicion has replaced strategy and identity has replaced evidence. If the US blocks Chinese students while maintaining that it wants to 'compete' with China, Beijing will likely frame the move as hypocritical — claiming it reveals American insecurity rather than confidence in its democratic model. The retaliatory measures may not just hurt bilateral relations but also signal to other countries the risks of aligning too closely with US policy on China. Yu's central claim is that Chinese students and scholars serve as covert extensions of the Chinese Communist Party (CCP), sent not to learn but to spy, steal, and subvert. This argument has gained traction in parts of Washington, where fears of intellectual property theft and technological competition are real and justified. But let's be clear: there is a vast difference between targeted counterintelligence and collective suspicion. To reduce an entire population of students — numbering over 270,000 annually — to latent threats is both empirically unfounded and strategically foolish. Chinese students are not a monolith. Many come precisely because they seek an alternative to the CCP's control. Some become critics of the regime. Others stay, contribute to US innovation, or build bridges that serve American interests abroad. Treating them as presumed agents of espionage doesn't protect US security — it undercuts America's greatest soft power asset: its openness. We are now witnessing the consequences of this worldview hardening into law. In May 2025, Secretary of State Marco Rubio, citing security risks, announced that his department would move to revoke or block Chinese student visas in 'sensitive' research fields outright, citing national security risks. The proposal would give broad authority to federal agencies to deny or cancel visas without due process, based not on individual conduct, but on nationality and field of study. This is not strategic caution — it's blanket exclusion. And it mirrors the logic of Yu's essay: that anyone Chinese by origin or association is inherently suspect. Such policies are dangerously close to the racialized fearmongering of the Chinese Exclusion Act era, now dressed in tech-sector clothing. They undermine US universities, punish innocent scholars, and hand the CCP a propaganda victory. If carried out, this policy won't stop espionage — it will cripple American research labs, isolate Chinese dissidents, and accelerate talent flight to competitor nations like Canada, the UK, and Australia. The Trump administration's aggressive stance on Chinese espionage is haunted by the very intelligence failures it now seeks to prevent. As Sue Miller, the CIA's former chief mole hunter, has pointed out, the collapse of US spy networks in China more than a decade ago — a debacle that saw scores of informants arrested or executed — remains unresolved. That strategic humiliation not only decimated on-the-ground intelligence, it also created a culture of institutional paranoia in Washington. Now, instead of rebuilding trust and refining intelligence practices, the Trump-era approach has leaned heavily on suspicion and overreach — particularly targeting ethnic Chinese scientists, scholars, and students. But blunt tools don't fix complex failures. The overcorrection has led to high-profile wrongful prosecutions, deteriorating academic collaboration and growing mistrust within diaspora communities. The United States' inability to root out past internal breaches has fueled a form of policy scapegoating — one that risks trading precision for profiling. Without credible reform of intelligence capabilities and transparent accountability for past missteps, the crackdown will remain reactive, politically charged and ultimately self-defeating. Yu frames UA-China academic collaboration as 'outsourcing,' suggesting the US has ceded control of its intellectual infrastructure to a hostile power. But this misunderstands both how American academia works and why it thrives. Academic exchange is not a one-way transaction. It's a competitive ecosystem, where ideas are tested, refined and challenged through global participation. Chinese students and researchers don't dilute US education — they elevate it. They help fill STEM classrooms, contribute to breakthroughs in AI and biomedical research, and keep US universities globally dominant. Cutting them off would hurt America far more than it would hurt China. Yes, vigilance is necessary. Research security protocols should be strong. Federal funding should come with guardrails. But throwing out the entire system of engagement, as Yu and now Rubio suggest, would be self-sabotage. If enforced, Rubio's proposal to ban Chinese students will not only undercut America's higher education system — it could also trigger swift retaliation from Beijing. China may impose reciprocal visa restrictions on US students, scholars and education programs, halt joint research initiatives or tighten controls on American academic access to Chinese data and field sites. More strategically, it could restrict elite talent from going to the US, incentivize a reverse brain drain or escalate a global narrative campaign accusing the US of racial discrimination. Such moves wouldn't just harm bilateral ties — they would damage America's soft power, alienate diaspora communities and send a troubling signal to other nations about the risks of engaging with US institutions. Ironically, by closing the door on Chinese students, Rubio and his allies may be doing more to weaken America's global leadership than to defend The U.S.-China contest is not just about chips, jets, and rare earths. It's about the future of global norms — openness versus control, pluralism versus authoritarianism. In this battle, academic freedom is not a vulnerability. It's a weapon. It is what makes the US different from — and stronger than — the system the CCP promotes. If we start mimicking Beijing's paranoia, walling off knowledge, and excluding people based on their passport, we risk becoming what we claim to oppose. Yu himself is living proof of that freedom's power. He came to the US seeking truth, found it in an open society and used it to shape national strategy. That's a success story, not a turn around now and advocate for closing the gates behind him is not only short-sighted — it's a betrayal of the very ideals that made his own story possible. A call for strategic openness Miles Yu transferred himself from Chinese student to gatekeeper by pulling up the ladder behind him. What we need is not blanket restriction but smart engagement, clearer funding rules, targeted export controls and honest dialogue with university leaders – and, yes, a robust national security posture. But we must resist fear-driven policies that punish potential allies and weaken our intellectual base. The best way to 'outcompete' China is not to become more like it — but to double down on what made the US the envy of the world. If we follow Yu's and Rubio's advice, we may win a battle of suspicion — but lose the war for global leadership. If the US wants to outcompete authoritarian regimes, it must stop mimicking their logic. Surveillance, guilt by association and ideological profiling are not strategies for innovation — they are symptoms of decline. Democracy's strength lies in openness, in attracting talent, and in offering a system that can inspire — not coerce — loyalty. Rather than banning students, the US should reinvest in the institutions that make it a magnet for global minds: its universities, its press, and its civic infrastructure. Journalists must be more careful not to amplify racialized suspicion. Lawmakers must recognize that brainpower, not fear, drives prosperity. Scholars like Miles Yu must reckon with the contradiction between their personal journeys and the policies they now advocate. Democracy does not win by closing its doors. It wins by proving it is worth entering. Yujing Shentu, PhD, is an independent scholar and writer on digital politics, international political economy and US-China strategic competition.
South China Morning Post
29-05-2025
- South China Morning Post
Environmental breakthroughs take centre stage in Hong Kong start-up pitch competition
Every early-stage company entering the 2025 EQT Impact Challenge recognised the need to come up with a business concept that could meet three key criteria: it had to be investible, scalable, and hold promise for the long term. The task was to convey that potential to a panel of expert jurors and demonstrate how the company's innovation could drive meaningful change. The pitch competition, which has held previous editions in Japan, South Korea and Singapore, aims to identify and support early-stage companies with their breakthrough concepts, business plans, financial models, and ambitions to scale for long-term growth. It is organised by EQT, one of the world's largest investment firms, with its philanthropic arm, EQT Foundation, providing the winning start-up capital to fuel growth, and access to a global network of potential industry partners and investors. The event is being held in partnership with the South China Morning Post. The competition focuses on novel, deep tech solutions and scientific breakthroughs related to climate and nature, as well as health and well-being. Many leading contenders were prepared to think big, putting forward ideas and solutions that, given the right backing and once scaled, have the potential to change lives on a global scale.
