What quantum physics tells us — and what may still remain beyond our present understanding
For centuries, the physical world was commonly imagined as something essentially mechanical: solid objects made of smaller solid objects, moving through space according to predictable laws.
Quantum physics changed that picture.
It did not make the physical world irrational, nor did it establish that anything is possible. Quantum mechanics is an extraordinarily successful scientific theory, capable of making predictions that have been confirmed with remarkable precision.
Yet the reality it describes is very different from the one suggested by everyday experience.
At the quantum scale, familiar concepts such as matter, position, separateness and certainty no longer work quite as intuitively as we expect them to.
Matter is not simply “solid”
An ordinary object feels solid because of the way its atoms and electrons interact. At the quantum level, however, matter cannot adequately be imagined as an assembly of tiny rigid balls.
Electrons, photons and other quantum entities are described by quantum states and can produce phenomena that appear particle-like in some experiments and wave-like in others.
The familiar distinction between “matter” and “wave” is therefore not sufficient to describe what happens at this scale.
This does not mean that matter is unreal. It means that the physical reality underlying what our senses perceive as solid objects is far more complex than appearance suggests.
Possibility is part of the physical description
At the heart of quantum mechanics is the wave function.
It contains the information needed to calculate the probabilities of the different results that may be obtained when a quantum system is measured.
This represents a profound departure from classical mechanics.
In ordinary classical physics, uncertainty can often mean that we simply do not possess enough information. Quantum mechanics places probability much more fundamentally within its description of physical systems.
Rather than giving us a miniature mechanical picture of what a particle is “really doing” at every instant, the theory gives extraordinarily accurate predictions about the possible results of physical interactions and measurements.
Reality at this level therefore cannot simply be described as a collection of objects permanently carrying all the fixed properties we intuitively assign to them.
Observation, measurement and the open question of consciousness
The word observation has a very specific meaning in quantum physics.
A quantum measurement is a physical interaction between a system and a measuring apparatus. The experimental arrangement determines which physical quantity is investigated and which outcomes can be recorded.
This has sometimes been extended into the popular claim that human consciousness directly creates physical reality. Quantum mechanics, as it currently stands, does not demonstrate this. A detector can interact with a photon without a human mind taking part in that physical interaction.
But this should not be transformed into the opposite assertion either.
Science has not demonstrated that consciousness can directly influence external matter through thought alone. It has also not established that every possible interaction between consciousness and physical reality is impossible.
Consciousness itself remains one of the major unresolved subjects of scientific enquiry.
Human beings also report experiences in which intention, expectation, attention and subsequent events appear meaningfully connected. Some interactions between mind and body are already well documented through psychology, neuroscience and physiology. Other reported phenomena remain controversial, difficult to reproduce or insufficiently understood.
Personal experience is not the same thing as controlled scientific evidence. Yet lack of scientific confirmation does not automatically constitute proof of non-existence.
A phenomenon may exist before we possess the concepts, instruments or experimental methods required to recognise and measure it.
The scientifically responsible position is therefore one of open enquiry: clearly distinguishing what has been demonstrated from what remains possible, unexplained or still beyond our present methods of investigation.
Entanglement challenges simple ideas of separateness
One of the most remarkable phenomena predicted by quantum mechanics is entanglement.
Two or more particles can share a quantum state in such a way that measurements performed on them display correlations that cannot be explained by ordinary classical models in which each object simply carries its own independent, locally predetermined properties.
Experiments testing Bell inequalities have confirmed these non-classical correlations; this body of work was recognised by the 2022 Nobel Prize in Physics awarded to Alain Aspect, John F. Clauser and Anton Zeilinger.
Although Entanglement seems to allow useful information to be transmitted instantaneously faster than light, its importance lies elsewhere: it forces us to reconsider the intuitive assumption that spatially separated things must always be completely describable as independent entities possessing their own separate sets of properties.
In quantum mechanics, the state of the whole system can contain relationships that cannot simply be reduced to a list of properties assigned independently to each part.
Energy, matter and a wider physical reality
Quantum physics is fundamental to our modern understanding of energy.
Here it is important to be precise. In physics, energy has a defined and measurable meaning; it is not automatically equivalent to what traditional, philosophical or healing systems may describe using the same word.
Quantum theory revealed that, in many physical systems, energy is exchanged in discrete amounts — quanta. It lies behind our understanding of atoms, photons, chemical bonds, semiconductors, lasers and much of modern technology.
Quantum mechanics therefore does not scientifically validate every phenomenon described as “energetic”.
What it has unquestionably done is undermine the old intuitive picture of reality as nothing more than separate, solid objects interacting in straightforward mechanical ways.
Matter, fields, probabilities, correlations and interactions form a physical world considerably stranger and more relational than everyday perception suggests.
That distinction leaves an important intellectual space.
We need not confuse the precise scientific meaning of energy with every other use of the term. But neither need we assume that the scientific concepts and instruments currently available to us already exhaust every possible aspect of the relationship between matter, living beings and consciousness.
A reality made of relationships as well as objects
Perhaps one of the most interesting changes brought by quantum physics is the importance it gives to relationships.
Interference depends upon relationships between quantum amplitudes. Entanglement concerns correlations between components of a system. Measurement itself is an interaction between physical systems.
This does not demonstrate that ancient traditions which spoke of interconnectedness had discovered quantum mechanics thousands of years ago. Their methods, languages and purposes were entirely different.
Yet the comparison can still be philosophically interesting.
Many ancient systems described reality through transformation, relationship, balance and complementary processes rather than exclusively as a collection of isolated objects. Modern physics arrived at its conclusions through mathematics, experimentation and increasingly sophisticated technology, but it too has discovered the limits of a purely mechanical picture of nature.
Similarity is not proof.
It can, however, be an invitation to ask better questions.
What we know — and what remains open
Quantum mechanics gives us powerful experimental reasons to abandon several simplistic assumptions about physical reality.
It tells us that matter cannot adequately be pictured as tiny pieces of solid substance; that quantum probabilities are fundamental to physical predictions; that the conditions under which measurements are performed matter; and that entangled systems display correlations without a classical equivalent.
What quantum physics does not currently demonstrate is that thoughts directly modify external physical reality, that consciousness itself is a quantum field, or that concepts such as qi, prana or other traditional notions of vital energy correspond to quantum energy as defined by physics.
But “not scientifically demonstrated” and “scientifically disproved” are not the same statement.
Scientific knowledge advances by developing ways to observe, quantify, test and reproduce phenomena. History repeatedly shows that nature does not wait for human beings to invent the instrument capable of measuring it.
An experience can therefore be real while its interpretation remains uncertain. A phenomenon can exist before its mechanism is understood. A scientific model can be extraordinarily successful without necessarily being the final description of everything reality contains.
Could consciousness interact with physical reality in ways that we do not yet understand?
Could intention, attention or other aspects of mind participate in processes that present scientific models do not adequately describe?
At present, these are open questions, not established scientific facts.
There is no need to convert them prematurely into certainties. There is equally no need to declare them impossible merely because our present instruments cannot verify them.
Curiosity and intellectual discipline can coexist.
A modern example: visualising a biphoton wave function
A striking example of how rapidly our ability to investigate the quantum world is developing comes from researchers at the University of Ottawa and Sapienza University of Rome.
Danilo Zia, Nazanin Dehghan, Alessio D’Errico, Fabio Sciarrino and Ebrahim Karimi developed an interferometric technique inspired by digital holography to reconstruct the amplitude and phase of spatial states involving correlated photons.
Traditional quantum-state tomography requires many separate projective measurements, with the number required increasing rapidly as the dimensionality of the system grows. The new approach combines an unknown biphoton state with a reference state and reconstructs information from coincidence imaging of their interference. The researchers report that their method produced a characterisation roughly three orders of magnitude faster than approaches used in previous experiments, with an average fidelity of 87%.
The public article describing the research attracted particular attention because of an image resembling the yin-yang symbol.
It is important to understand what that image actually represents.
The yin-yang did not spontaneously emerge from the quantum system. The researchers deliberately used a pump beam shaped as the symbol and then demonstrated that their technique could reconstruct the amplitude and phase structure encoded in the resulting biphoton state.
So the experiment did not reveal the Tao hidden inside matter.
What it did reveal is remarkable enough: contemporary technology can now reconstruct extraordinarily complex information carried by correlated quantum states in a fraction of the time previously required.
And the episode offers an additional lesson.
It is tempting to use new scientific discoveries as confirmation of ideas we already hold. A more interesting approach is to allow science to tell us precisely what it has discovered — and then remain curious about the much larger territory it has not yet explained.
About the research
The study “Interferometric imaging of amplitude and phase of spatial biphoton states” was published in Nature Photonics, Volume 17, pages 1009–1016, in 2023.
The authors are Danilo Zia, Nazanin Dehghan, Alessio D’Errico, Fabio Sciarrino and Ebrahim Karimi.
Danilo Zia and Fabio Sciarrino are affiliated with the Department of Physics at Sapienza University of Rome, Italy.
Nazanin Dehghan, Alessio D’Errico and Ebrahim Karimi are affiliated with Nexus for Quantum Technologies, University of Ottawa, Canada. Ebrahim Karimi is also affiliated with the National Research Council of Canada. Dehghan and D’Errico contributed equally to the work.
Original research: Interferometric imaging of amplitude and phase of spatial biphoton states, Nature Photonics.
Original article: “Visualizing the mysterious dance: Quantum entanglement of photons captured in real-time”, published by Phys.org on 21 August 2023, from material provided by the University of Ottawa.
