Speaker 1: Welcome to the quart Side Quantum Physics Podcast, an exploration
Speaker 1: of the fundamental structure of reality, where quantum laws govern matter, energy,
Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
Speaker 1: and understanding begins at the smallest scales.
Speaker 2: So there is this really persistent idea in astronomy, and honestly,
Speaker 2: I think it's just human nature at this point. If
Speaker 2: you want to see something better, or you see something
Speaker 2: further away, you just need to build something bigger.
Speaker 3: Right the classic light bucket philosophy.
Speaker 2: Exactly the light bucket. You want to see a faint star,
Speaker 2: build a bigger bucket to catch the light. You want
Speaker 2: to see a smaller detail, build a wider mirror to
Speaker 2: sharpen the image. It's a very brute force.
Speaker 3: Approach, it is. But to be fair, it has served
Speaker 3: us incredibly well for about four hundred years. I mean,
Speaker 3: from Galileo's first spyglass all the way to the James
Speaker 3: webspased telescope. The fundamental logic has remained entirely consistent. More
Speaker 3: surface area equal more photons and more photons equal better resolution.
Speaker 2: Yeah, that makes total sense. But we are doing a
Speaker 2: deep dive today into a stack of papers specifically focusing
Speaker 2: on a proposal published in Physical Review Letters in February
Speaker 2: twenty twenty six that suggests we are finally hitting.
Speaker 3: A wall, a hard physical wall, yes right.
Speaker 2: A wall where building bigger just isn't feasible anymore. The
Speaker 2: team behind this research involves folks from the University of Arizona,
Speaker 2: the University of Maryland, and the NASA Goddard Space Flight Center,
Speaker 2: and their argument is absolutely fascinating.
Speaker 3: It really is. They are basically saying that to take
Speaker 3: the next massive leap in seeing the universe, we don't
Speaker 3: need to pour more glass. We need to completely hack
Speaker 3: the physics of light itself.
Speaker 2: Which brings us to the core mission of our deep
Speaker 2: dive today. For you listening, we are going to unpack
Speaker 2: how scientists plan to build Earth sized telescopes without actually
Speaker 2: building a single Earth sized physical object.
Speaker 3: It is a complete paradigm shift, and I really don't
Speaker 3: use that phrase lightly. We're looking at a proposal that
Speaker 3: effectively suggests replacing the physical transportation of gathered starlight with
Speaker 3: quantum teleportation.
Speaker 2: Quantum teleportation, that is the exact headline that stopped me
Speaker 2: in my tracks. It sounds like science fiction or a
Speaker 2: comic book. Movie plot. But this is serious, peer reviewed
Speaker 2: academic work. The paper is titled super Resolution Imaging with
Speaker 2: Entanglement Enhanced Telescopy.
Speaker 3: And if this protocol works, we aren't just talking about
Speaker 3: getting a slightly sharper picture of a distant star cluster.
Speaker 3: We are talking about decoupling the resolution of a telescope
Speaker 3: from its physical size and location, entirely.
Speaker 2: Creating a virtual giant using the laws of quantum mechanics.
Speaker 2: So before we get to the quantum magic, and it
Speaker 2: really does feel like magic, we need to rigorously understand
Speaker 2: the status quo. Why can't we just keep building bigger mirrors,
Speaker 2: or more specifically, why is the current method of combining
Speaker 2: multiple telescopes so incredibly difficult.
Speaker 3: To understand that we have to start with the concept
Speaker 3: of long baseline interferometry. This is currently the gold standard
Speaker 3: for high resolution imaging in astronomy.
Speaker 2: Okay, let's unpack that definition for the listener. What is
Speaker 2: long baseline interferometry technically speaking?
Speaker 3: Right, So, in its technical application, interferometry is the practice
Speaker 3: of combining electromagnetic signals, which in this context is visible
Speaker 3: starlight collected by multiple spatially separated telescopes. So imagine you
Speaker 3: have telescope A and.
Speaker 2: Telescope B, and they are separated by a good distance, right,
Speaker 2: say a kilometer.
Speaker 3: Exactly separated by one kilometer. Now separately, there are just
Speaker 3: two modest instruments. But if you can take the light
Speaker 3: caught by telescope A and a light cought by telescope
Speaker 3: B and physically combine those light beams at a central point,
Speaker 3: you trick the physics. You create what we call an
Speaker 3: effective aperture.
Speaker 2: An effective aperture, so the universe essentially behaves as if
Speaker 2: it's being observed by one giant mirror that spans that
Speaker 2: entire one kilometer distance between them.
Speaker 3: Precisely, you achieve the resolution the sharpness of a telescope
Speaker 3: with a one kilometer wide mirror, even though physically you
Speaker 3: mostly just have empty dirt and air between the two facilities.
Speaker 3: The baseline is that distance between the furthest individual telescopes
Speaker 3: in your array, the longer the baseline, the sharper the
Speaker 3: image you can reconstruct.
Speaker 2: Now this sounds a lot like how we got that
Speaker 2: famous image of the black hole a few years back,
Speaker 2: right the event horizon telescope that was basically an earth
Speaker 2: sized virtual telescope that is a.
Speaker 3: Very crucial comparison to make, but there is a major
Speaker 3: catch there. The event horizon telescope use radio waves. Radio
Speaker 3: waves are long, lazy wavelengths. They are roughly a millimeter
Speaker 3: or more long, and because they are so slow and
Speaker 3: large in a physical sense, you can literally record the
Speaker 3: incoming wave data onto hard drives at each telescope.
Speaker 2: Oh, I see, you just stamp a timecode on the data.
Speaker 3: Exactly, you stamp a GPS timecode on it, put the
Speaker 3: hard drives in a FedEx box, shift them to a
Speaker 3: supercomputer facility, and combine the waves digitally. Months later.
Speaker 2: You can just record the wave and play back. But
Speaker 2: we are talking about optical astronomy today visible light.
Speaker 3: Right with visible light, the wavelengths are tiny. We are
Speaker 3: talking hundreds of nanometers. They oscillate at frequencies of hundreds
Speaker 3: of terror herds. You absolutely cannot record the wave of
Speaker 3: a single photon on a hard drive and combine it later.
Speaker 3: The technology to digitize a LightWave at that speed simply
Speaker 3: doesn't exist.
Speaker 2: So to do enterferometry with visible light, you have to
Speaker 2: combine the actual physical light waves in real time.
Speaker 3: You do, which means if you have a telescope in
Speaker 3: Arizona and a telescope in Maryland. You literally have to
Speaker 3: transport the photon from Arizona to a central lab and
Speaker 3: the photon from Maryland to that same lab without those
Speaker 3: photons dying or getting out of sink.
Speaker 2: And that brings us to the primary villain of our
Speaker 2: story today, the physical optical link, or as the source
Speaker 2: material frames it in engineering terms, the beam splitter bottleneck.
Speaker 3: It is an absolute nightmare for engineers. Just think about
Speaker 3: the logistics involved. You need to transport a f fragile
Speaker 3: optical beam over miles of terrain. Usually this is done
Speaker 3: using vacuum tubes, literally burying light pipes in the ground
Speaker 3: containing a series of perfect mirrors to bounce the light along.
Speaker 3: Or alternatively, you try to use fiber optic cables.
Speaker 2: But wait, we use fiber optics for the Internet all
Speaker 2: the time. I can send an email to Australia and
Speaker 2: it gets there in milliseconds. Why can't I just send
Speaker 2: a star photon to Australia through the same cable.
Speaker 3: Because when you send an email, you are sending classical
Speaker 3: digital pulses, a bright flash for a one, a dim
Speaker 3: flash for a zero. If that signal gets weak after
Speaker 3: fifty kilometers of fiber. A repeater station reads the one
Speaker 3: or zero boosts it creates a fresh, loud copy and
Speaker 3: sends it on its way.
Speaker 2: But you can't copy a photon's quantum state bingo.
Speaker 3: The no cloning theorem in quantum mechanics strictly forbids it.
Speaker 3: You cannot amplify or copy an unknown quantum state without
Speaker 3: destroying the original information encoded within it. And in this case,
Speaker 3: the specific phase information of the starlight is exactly which
Speaker 3: you need to preserve for the interferometry to work.
Speaker 2: So you are forced to send the original exact photon
Speaker 2: that hit the telescope mirror. You have to guide that
Speaker 2: one fragile little packet of energy through kilometers of glass,
Speaker 2: fiber or.
Speaker 3: Vacuum tube, and no material in the universe is perfectly
Speaker 3: transparent over a few kilometers. The glass simply absorbs or
Speaker 3: scatters the photon. It's a process called attenuation.
Speaker 2: Ah So by the time the light from two very
Speaker 2: distant telescopes actually meets in the middle lab, you've lost
Speaker 2: so much signal that there's nothing left to combine.
Speaker 3: The signal is effectively gone. The transport loss places a
Speaker 3: hard physical cap on how big our telescope array can be.
Speaker 3: We simply can't build a ten kilometer optical array using
Speaker 3: classical methods because the light dies in the pipe before
Speaker 3: it ever reaches the mixing station.
Speaker 2: Which explains why current arrays like the Chara array or
Speaker 2: the VLTI are limited to baselines of just a few
Speaker 2: hundred meters. We want to go to kilometers or even thousands.
Speaker 3: Of kilometers, and conventional interferometry simply cannot scale to those distances.
Speaker 3: The transport losses are two high, and the engineering complexity
Speaker 3: of maintaining phased ability keeping the light waves perfectly in
Speaker 3: sync in a vacuum tube that long is functionally impossible.
Speaker 2: So we are stuck. We desperately want the resolution of
Speaker 2: a giant telescope, but we can't transport the light to
Speaker 2: combine it. This is exactly where the research from Padilla,
Speaker 2: Guha and Sogdod comes. In their paper super Resolution Imaging
Speaker 2: with entanglement Enhanced Telescopy proposes a radical solution to the
Speaker 2: light pipe problem.
Speaker 3: Their solution is brilliant in its sheer audacity. They propose
Speaker 3: that we simply don't transport the light at all.
Speaker 2: Okay, but if I don't transport the light to a
Speaker 2: central hub. I can't physically interfere the beams. And if
Speaker 2: I can't interfere the beams, I don't get the high
Speaker 2: resolution image. I mean, that is the entire definition of interferometry.
Speaker 3: In classical physics. Yes, you are completely correct, but this
Speaker 3: team is applying quantum information theory to optics. They are
Speaker 3: positing a fundamental foundational shift in how we think about
Speaker 3: gathering light.
Speaker 2: They are saying we should stop treating light like a
Speaker 2: classical wave that needs to be guided through a plumbing
Speaker 2: system of mirrors and tubes.
Speaker 3: Exactly, they are suggesting we treat the light strictly as
Speaker 3: a quantum object that carries information. This is a very
Speaker 3: important distinction that doctor Psychott Guha makes in the foundational material.
Speaker 3: He rigorously separates quantum optics from quantum information theory.
Speaker 2: Right, let's look at that distinction. He defines quantum optics
Speaker 2: as the quantum theory of light itself, studying how photons
Speaker 2: physically interact with atoms and mirrors.
Speaker 3: Yes, whereas he defines quantum information theory or qiit as
Speaker 3: the mathematical science of quantifying the actual information carried by
Speaker 3: those inherently quantum physical media Qit asks an entirely different
Speaker 3: question than classical optics.
Speaker 2: It asks what is the absolute theoretical maximum amount of
Speaker 2: data I can extract from this quantum state, regardless of
Speaker 2: the physical hardware I used to measure it.
Speaker 3: Precisely, they're moving away from a hardware problem, how do
Speaker 3: I build a longer clear glass pipe, to a fundamental
Speaker 3: data processing problem. They're looking strictly at nature's fundamental limits
Speaker 3: regarding information.
Speaker 2: Let's talk about those limits. In classical optical theory, astronomers
Speaker 2: are always battling something called the Railey limit or the
Speaker 2: diffraction limit.
Speaker 3: The blur limit. If you look at two stars that
Speaker 3: are extremely close together in the sky, your telescope just
Speaker 3: is one blurry, elongated blob of light. You mathematically cannot
Speaker 3: tell if it's one star or two.
Speaker 2: And for centuries we just accepted that blur as an
Speaker 2: unbreakable law of physics, a limitation of the universe.
Speaker 3: But the researchers at the Center for Quantum Networks argue
Speaker 3: that the Railey limit is actually just a bad habit.
Speaker 3: It is a limitation of our specific receivers, our lenses
Speaker 3: and camera sensors, not a limitation of the light itself.
Speaker 2: Meaning the information about the two distinct stars is actually
Speaker 2: there in the light hitting the mirror, we just aren't
Speaker 2: catching it properly.
Speaker 3: That is exactly the case. The photons arriving at your
Speaker 3: telescope contain the full necessary quantum information required to distinguish
Speaker 3: those two stars. Do we smash those delicate photons onto
Speaker 3: a focal plane camera.
Speaker 2: Sensor which just measures brightness intensity?
Speaker 3: Right, a camera pixel just counts how many photons hit it.
Speaker 3: In doing so, it aggressively destroys the delicate quantum information,
Speaker 3: the phase, the spatial distribution. We're essentially using a blunt
Speaker 3: instrument to measure something incredibly fragile.
Speaker 2: So we need a sharper instrument, And the paper introduces
Speaker 2: a concept called the quantum Fisher information mandate.
Speaker 3: The quantum Fisher information or QFI is the theoretical ceiling
Speaker 3: of knowledge. It represents the absolute maximum amount of information
Speaker 3: you can possibly extract from a quantum system about a
Speaker 3: specific parameter.
Speaker 2: And in this astrophysical context, that parameter is the angular
Speaker 2: separation of the two stars, the tiny distance between them
Speaker 2: in the sky.
Speaker 3: Correct, the researchers proved mathematically that if you build a
Speaker 3: receiver that respects the QFI mandate. A receiver that extracts
Speaker 3: the quantum information rather than just the classical intensity. The
Speaker 3: traditional RAILI limit effectctively disappears.
Speaker 2: That is staggering. You can resolve objects that astronomers previously
Speaker 2: considered entirely unseeable.
Speaker 3: Provided you collect enough data over time. Yes, standard receiver
Speaker 3: techniques are totally suboptimal. Quantum limits allow for a resolution
Speaker 3: that makes the traditional diffraction limit look like a historical artifact.
Speaker 2: Okay, so that covers the theoretical framework. The theory says
Speaker 2: we can see the unseeable if we stop using standard
Speaker 2: cameras and start processing quantum information. But I want to
Speaker 2: get into the actual mechanics of this. If we aren't
Speaker 2: using light pipes to connect the observatories, how do the
Speaker 2: two distant telescopes actually talk to each other to form
Speaker 2: an image.
Speaker 3: This brings us to the architecture of entanglement enhanced telescopy.
Speaker 3: The proposed receiver design eliminates the physical optical link entirely. Instead,
Speaker 3: two or more distant telescopes share a unified quantum state.
Speaker 2: And this architecture relies on three major cutting edge components.
Speaker 2: A spatial mode sorter atomic, quantum memories, and teleportation via entanglement.
Speaker 3: Let's break those down sequentially, starting with the first thing
Speaker 3: the starlight hits after the primary mirror component One is
Speaker 3: the spatial mode sorder or Spady.
Speaker 2: Spade replaces the traditional camera sensor at the focal plane.
Speaker 2: But looking at the diagrams and the source material specifically
Speaker 2: Figure one B, it really doesn't operate anything like a
Speaker 2: standard camera.
Speaker 3: It doesn't think about what a traditional camera does. It
Speaker 3: asks a very simple question, where did the photon land
Speaker 3: on the grid? It maps X and y coordinates to
Speaker 3: create an image. A spatial mode sorder asks a completely
Speaker 3: different question. It asks what is the specific geometric shape
Speaker 3: of the photon's wavefront?
Speaker 2: The shape of the wavefront. When I think of a photon,
Speaker 2: I usually just think of a tiny, localized point of light,
Speaker 2: a particle.
Speaker 3: In quantum optics, you have to think of light arriving
Speaker 3: from a distant source as having a spatial distribution. It
Speaker 3: exists as a wave that excites specific spatial modes. I
Speaker 3: find a musical analogy works best here.
Speaker 2: Oh, I like that, Let's hear it.
Speaker 3: Think of the light entering the telescope aperture as a
Speaker 3: complex musical chord. A normal camera center just acts like
Speaker 3: a simple decibel meter. It just hears loud noise and
Speaker 3: measures the total volume.
Speaker 2: It just measures the intensity of the light exactly.
Speaker 3: But the spade device acts like a highly trained musician
Speaker 3: with perfect pitch. It listens to that same chord, breaks
Speaker 3: the noise down and says that sound is composed of
Speaker 3: a C sharp an E and a G it D
Speaker 3: multiplexes the incoming photon into orthogonal spatial patterns prior to detection.
Speaker 2: Can we visualize these spatial patterns? What do these modes
Speaker 2: actually look like?
Speaker 3: Imagine pointing a laser pointer at a wall. The bright,
Speaker 3: perfectly round dot in the center is what we call
Speaker 3: the fundamental mode.
Speaker 2: Just a single solid circle of light.
Speaker 3: Right now, imagine a different shape. Imagine two distinct lobes
Speaker 3: of light side by side with a dark empty line
Speaker 3: right down the middle. It looks a bit like a dumbbell.
Speaker 3: That is a higher order spatial mode. Or imagine a
Speaker 3: pattern that looks like a four leaf clover, and the
Speaker 3: starlet actually naturally takes on these complex shape. The wave
Speaker 3: function the light does. Yes, when you have a single
Speaker 3: perfectly centered star, the light mostly arrives in that simple
Speaker 3: fundamental circular mode. But when two stars are very close together,
Speaker 3: closer than the Railey limit, their combined light field is
Speaker 3: slightly displaced.
Speaker 2: And that tiny physical displacement alters the wave exactly.
Speaker 3: The displacement causes the incoming light to excite those higher
Speaker 3: order shapes, the Dumbbell mode or the Clover mode. The
Speaker 3: Spade device is designed to physically separate these different shapes
Speaker 3: into different output channels.
Speaker 2: So if your detector sitting at the end of the
Speaker 2: Dumbell channel registers of photon, you know instantly that the
Speaker 2: source isn't just a single centered star.
Speaker 3: You know instantly that there is a second star there,
Speaker 3: or that the singular source is slightly off center. Unlike
Speaker 3: a camera that just records a blurry blob, the Spade
Speaker 3: device analyzes the specific mode to extract a much richer
Speaker 3: layer of information about the angular separation of the source.
Speaker 2: Knowing which mode was excited tells you exponentially more about
Speaker 2: the target than just knowing where a dot landed on
Speaker 2: a CCD chip. That is how they begin to reach
Speaker 2: that quantum Fisher information.
Speaker 3: Limit correct, So that is step one. Telescope A catches
Speaker 3: a photon and runs it through the Spady sorder which
Speaker 3: identifies the spatial mode. Say it's the Dumbbell mode in
Speaker 3: time bin number five.
Speaker 2: But now we hit a wall again. You have this
Speaker 2: vital piece of mode information at Telescope A in Arizona,
Speaker 2: but you can't just text or email that data to
Speaker 2: Telescope B in Maryland, right because true inefrometry requires comparing
Speaker 2: the quantum phase of the light, and any classical measurement
Speaker 2: you make destroys that phase.
Speaker 3: Right. If you measure the photon right then and there
Speaker 3: to see its phase, you collapse its wave function. You
Speaker 3: permanently lose the quantum correlation with the light hitting the
Speaker 3: other telescope.
Speaker 2: So you have to somehow save that fragile quantum state
Speaker 2: until you can properly compare it with the state at
Speaker 2: the other facility.
Speaker 3: Which brings us to component two atomic quantum memories. You
Speaker 3: need a storage.
Speaker 2: Medium, essentially a hard drive for starlight.
Speaker 3: A quantum hard drive. You have to take that fragile
Speaker 3: photonic state that just came out of the Spade device
Speaker 3: and map it onto an atomic structure. The source material
Speaker 3: specifically focuses on using atomic quantum memories such as silicon
Speaker 3: vacancies in a diamond lattice.
Speaker 2: Silicon vacancies. These are engineered flaws inside a diamond.
Speaker 3: Right, Yes, they are highly specific, artificially created defects. These
Speaker 3: vacancies have free electrons that act as quibots. They have
Speaker 3: a quantum spin state that can be precisely manipulated by
Speaker 3: lasers and microwaves.
Speaker 2: How do you get the starlight into the diamond though?
Speaker 3: The process involves routing the sordied photon into the memory
Speaker 3: using what is called a photon memory cnot gate.
Speaker 2: A cnot gate that is a logic operation from quantum computing,
Speaker 2: controlled not exactly.
Speaker 3: It operates as a fundamental quantum logic gait. The system
Speaker 3: takes the incoming photon and forces it to interact with
Speaker 3: the electron and the diamond defect. Through this interaction, the
Speaker 3: quantum state of the photon, its phase, its mode information
Speaker 3: is effectively mapped onto the spin state of that local
Speaker 3: memory quibit.
Speaker 2: So the original starlight photon is absorbed and gone, but
Speaker 2: its exact quantum information, it's ghost basically is now safely
Speaker 2: trapped in the electrons spin of this diamond atom.
Speaker 3: At telescope A precisely and Concurrently, the exact same process
Speaker 3: is happening with a different photon from the same star
Speaker 3: over at telescope B.
Speaker 2: So now you have two diamonds sitting in labs potentially
Speaker 2: thousands of kilometers apart, and each one is holding half
Speaker 2: of the quantum information from the star system.
Speaker 3: And now you face the ultimate challenge. How do you
Speaker 3: combine the information in those two diamonds without moving them
Speaker 3: and without a physical wire connecting them.
Speaker 2: This is the real cliffhanger of the architecture, and the
Speaker 2: answer is component three teleportation via entanglement.
Speaker 3: Before the astronomical observation even begins, the system operators have
Speaker 3: to predistribute entangled pairs of quibbits to both telescope sites.
Speaker 2: Spooky action at a distance, as Einstein called it.
Speaker 3: It serves as the invisible bridge. Station A holds one
Speaker 3: half of an intangled pair and station B holds the
Speaker 3: other half. As doctor Guha notes, in the theoretical framework,
Speaker 3: quantum entanglement is a correlation that is fundamentally stronger than
Speaker 3: any probabilistic correlation allowed by classical physics.
Speaker 2: So how does the bridge actually work. You have the
Speaker 2: starlight memory and you have the entangled memory. Sitting next
Speaker 2: to it, you.
Speaker 3: Execute a teleportation protocol. At each telescope site, you perform
Speaker 3: a very specific joint measurement, an X basis measurement on
Speaker 3: both the local diamond memory holding the starlight and the
Speaker 3: local half of the entangled pair simultaneously.
Speaker 2: You measure them together. Does that transport the starlight to
Speaker 2: the other lab.
Speaker 3: It doesn't transport the physical atom or a photon, but
Speaker 3: it mimics the exact mathematical result of physical optical interference.
Speaker 3: By performing these measurements at both sites and then sharing
Speaker 3: the results of those measurements over a standard classical internet connection.
Speaker 2: Wait, a normal internet connection the classical channel mentioned in
Speaker 2: the outline, Yes.
Speaker 3: A standard fiber optic internet line. By combining the local
Speaker 3: measurem data with the data sent over the classical channel,
Speaker 3: the supercomputer can reconstruct exactly what would have happened if
Speaker 3: you had physically overlapped the two starlight beams in a
Speaker 3: central lab.
Speaker 2: I want to make sure the listener really grasps this,
Speaker 2: because it is mind bending. The physical starlight from telescope
Speaker 2: A never touches the starlight from telescope B.
Speaker 1: Never.
Speaker 2: They never physically interact. Instead, you are combining the measured
Speaker 2: data about the light using the pre shared entangled pairs
Speaker 2: as a sort of cryptographic decoder ring to unlock the
Speaker 2: phase relationship.
Speaker 3: That is a perfect analogy. The pre shared entanglement acts
Speaker 3: as a perfectly synchronized shared reference frame across the continent.
Speaker 3: It allows you to create virtual interference. The system perfectly
Speaker 3: mimics the mathematical interference pattern without the beams ever having
Speaker 3: to touch.
Speaker 2: You are literally teleporting the electromagnetic reality of the photon
Speaker 2: across a network.
Speaker 3: But hold on, I have a logistical question here. We
Speaker 3: established earlier that you can't send starlight photons through long
Speaker 3: fiber optic cables because of attenuation and transport loss.
Speaker 2: Correct they get absorbed by the glass.
Speaker 3: Why doesn't that exact same loss problem apply to distributing
Speaker 3: the entangled pairs. If I try to send half of
Speaker 3: an entangled photon pair from Arizona to Maryland to set
Speaker 3: up this bridge, won't you just die in the fiber two?
Speaker 2: You are absolutely right to ask that it is the
Speaker 2: exact same physical limitation. If you try to send an
Speaker 2: entangled photon directly over one thousand kilometers of fiber, it
Speaker 2: will almost certainly be lost So.
Speaker 3: Aren't we just back to square one. We still have
Speaker 3: a distance limit.
Speaker 2: We would be except for one crucial difference. For the
Speaker 2: entangled pairs. We can utilize the technology called quantum repeaters,
Speaker 2: and this relies on a process known as entanglement swapping.
Speaker 3: Entanglement swapping walk us through how that circumvents the distance limit.
Speaker 2: Imagine you have a chain of intermediate stations spaced every
Speaker 2: fifty kilometers between Arizona and Maryland, Okay, a daisy chain
Speaker 2: of nodes.
Speaker 3: Station A creates an entangled pair with station B. Station
Speaker 3: B simultaneously creates a separate entangled pair with station C.
Speaker 2: So A is linked to B and B is linked
Speaker 2: to C. But A and C don't know each other exactly.
Speaker 3: But then the operator at station B performs a specific
Speaker 3: joint measurement on its two local halves. This measurement destroys
Speaker 3: the entanglement at station B, but in doing so, it
Speaker 3: magically stitches together the quebit at station A and the
Speaker 3: quibitt at station C.
Speaker 2: It swaps the entanglement down the lines. Now A and
Speaker 2: C are directly entangled, even though they never interacted.
Speaker 3: Yes, you can hopscotch the entanglement. Connection across an entire continent, and.
Speaker 2: Why can't we just do that with the original starlight
Speaker 2: photon because.
Speaker 3: Of the no cloning theorem we discussed. To do the swap,
Speaker 3: you have to manipulate and measure the quantum state. If
Speaker 3: you try that with the unknown starlight photon, you destroy
Speaker 3: the exact spatial and phase information you are trying to measure.
Speaker 2: AH. But with the entangled pairs, you generate them yourself.
Speaker 2: You know their state. If you lose one in the fiber,
Speaker 2: you just generate another one until the swap succeeds precisely.
Speaker 3: You can rebuild the road the entangled bridge as you go,
Speaker 3: taking as much time as you need before the observation,
Speaker 3: but you cannot rebuild the car the starlight photon once
Speaker 3: it arrives.
Speaker 2: That is the critical distinction. You establish the continent wide
Speaker 2: entangled link first using repeaters, and then you use that
Speaker 2: established link to catch and teleport the starlight. This completely
Speaker 2: changes the operational process of an observatory lift or walk
Speaker 2: through the actual data acquisitions step by step.
Speaker 3: Let's do it. So you are sitting at the console
Speaker 3: of this massive quantum ray. Step one, A photon from
Speaker 3: a distant star cluster arise at Site A and Site
Speaker 3: B simultaneously.
Speaker 2: Step two, the spade device at each telescope captures the
Speaker 2: photon d multiplexes it and identifies the spatial moli it registers,
Speaker 2: say mode two time bin fourteen.
Speaker 3: Step three, that specific mode information is compressed and loaded
Speaker 3: onto the local quantum memory registers the silicon vacancies in
Speaker 3: the diamond.
Speaker 2: Step four the network phase, the system leverages the pre
Speaker 2: shared entanglement bridge to perform the sequence of xbas measurements
Speaker 2: on the diamond memories.
Speaker 3: And finally, step five, the computers at each site generate
Speaker 3: a single bit post processed outcome based on those measurements.
Speaker 2: A single bit outcome, Wait a one or a zero?
Speaker 3: Yes, just a binary one or zero.
Speaker 2: He used to get these incredibly beautiful full color images
Speaker 2: from the Hubble or James web. And now, after all
Speaker 2: this quantum teleportation, we get a single bit that seems
Speaker 2: incredibly sparse.
Speaker 3: It is remarkably sparse. You certainly do not get an
Speaker 3: image from a single phogon. But this is where the
Speaker 3: statistical reconstruction comes in. You collect these single bit outcomes
Speaker 3: over measurements of millions of time blocks, each containing one photon.
Speaker 2: Event you aggregate the data.
Speaker 3: You aggregate massive amounts of data. By collecting these empirical
Speaker 3: probabilities over time, you build up a very precise statistical distribution.
Speaker 2: And from that massive pile of ones and zeros, the
Speaker 2: supercomputer can estimate the parameter we are looking for.
Speaker 3: Yes, the system uses those statistics to estimate theta, the
Speaker 3: angular separation between the stars. And because the entire architecture
Speaker 3: is mandated by the quantum fissure information limit, the precision
Speaker 3: of that estimation is entirely off the charts.
Speaker 2: The resolution scales directly with the baseline to aperture diameter
Speaker 2: ratio correct.
Speaker 3: Because you have eliminated the transport loss, you can push
Speaker 3: the baseline out to thousands of kilometers. This technical consideration
Speaker 3: allows you to estimate parameters at the absolute quantum limit.
Speaker 2: It is really instructive to compare this quantum method to
Speaker 2: the classical baseline we discussed earlier. In classical white light interferometry,
Speaker 2: the astronomers are literally sliding physical mirrors back and forth
Speaker 2: on tracks.
Speaker 3: Right they are They physically vary the phase delay by
Speaker 3: moving mirrors until one output port is at its absolute
Speaker 3: brightest and the other is totally dark. It is a
Speaker 3: mechanical scanning.
Speaker 2: Process, and from that they extract the data. They estimate
Speaker 2: the phase difference and the intensity difference to mathematically reconstruct
Speaker 2: the image. But doctor Sajod offers a strong critique of
Speaker 2: this classical method in the paper he does.
Speaker 3: He points out that while this physical sliding mirror method
Speaker 3: mimics phase scanning, it is fundamentally not the quantum optimal
Speaker 3: method for quantitative imaging problems.
Speaker 2: Because it throws away information.
Speaker 3: Yes, it wastes the crucial spatial mode data in favor
Speaker 3: of a simple blunt brightness check. It operates well below.
Speaker 2: The quantum limit, but the quantum network method gives researchers
Speaker 2: a massive new advantage. The outline calls it the arbitrary
Speaker 2: measurement basis.
Speaker 3: This is a huge leap forward in flexibility. Think about
Speaker 3: a physical glass telescope. Your measurement basis is rigidly fixed
Speaker 3: by the hardware you polished a specific glass lens. You
Speaker 3: are permanently stuck with exactly what that lens does to
Speaker 3: the light.
Speaker 2: If you want to measure the light differently, you have
Speaker 2: to build a new instrument exactly.
Speaker 3: But in this quantum network architecture, the lens is effectively software.
Speaker 3: The measurement basis consists entirely of the sequence of quantum
Speaker 3: logic gates you apply to the local memory after the
Speaker 3: photon has been absorbed.
Speaker 2: Oh wow, so you can change how you analyze the
Speaker 2: light after you've already caught it.
Speaker 3: You can perform any arbitrary measurement on the collective light
Speaker 3: field simply by reprogramming the quantum operations applied to the
Speaker 3: diamond memory. It allows researchers a level of flexibility that
Speaker 3: is physically impossible with classical mirrors.
Speaker 2: It is essentially a software defined telescope, and that allows
Speaker 2: for incredible scalability too, doesn't.
Speaker 3: It vastly improved scalability. Classical physical beam combination becomes exponentially
Speaker 3: more complex and lossy with every new telescope you add
Speaker 3: to the array. Trying to perfectly align light from ten
Speaker 3: telescopes in a vacuum tube system is a nightmare.
Speaker 2: But the quantum method just requires adding another node to
Speaker 2: the entanglement network.
Speaker 3: Right. It generalizes beautifully to multiple telescope systems, and the
Speaker 3: ultimate advantage is loss mitigation. Removing the physical transmission loss
Speaker 3: associated with bringing light to a central hub allows for
Speaker 3: much longer baselines, which directly translates to exponentially higher resolution.
Speaker 2: Oh, let's shift gears and talk about the history and
Speaker 2: development of this field, because reading this, it's easy to
Speaker 2: get lost in the theoretical magic, but real teams of
Speaker 2: people have been working on this for years to make
Speaker 2: it a reality.
Speaker 3: We absolutely have to contextualize this. The NASA and Arizona
Speaker 3: proposal did not just emerge fully formed out of nowhere.
Speaker 3: It rests heavily on vital precursors and theoretical foundations, most
Speaker 3: notably the source material sites, the groundbreaking work of Gotsman,
Speaker 3: Generine and Croke. Back in twenty.
Speaker 2: Twelve, the team from the University of Waterloo in the
Speaker 2: Perimeter Institute.
Speaker 3: Yes, they were among the very first to mathematically propose
Speaker 3: the concept of interfering remote light sources using entanglement without
Speaker 3: ever physically combining the beams. They laid the theoretical groundwork.
Speaker 2: The visionaries who did the math. But doing the math
Speaker 2: is one thing. Actually building it is another, and that
Speaker 2: is where the Harvard University group comes in, led by
Speaker 2: Professor Mikhal Lukean.
Speaker 3: The Harvard group is critical here because they provided the
Speaker 3: actual proof of concept demonstration in the laboratory, they successfully
Speaker 3: demonstrated entanglement assisted differential.
Speaker 2: Faith measurement, and the specific technology they used for that
Speaker 2: demonstration is exactly what we've been discussing. They utilized remote
Speaker 2: photonically heralded entanglement among atomic quantum memories using silicon vacancies
Speaker 2: in diamond.
Speaker 3: It is the exact hardware foundation cited in the current proposal.
Speaker 3: The Padia and Guha paper is essentially taking that successful
Speaker 3: lab bench experiment and scaling it up to an observatory level.
Speaker 2: The evolution of this NASA and Arizona study also tracks
Speaker 2: closely with the prior work of doctor Aquil Sadjad.
Speaker 3: It does doctor Sajod had previously focused deeply on quantifying
Speaker 3: the fundamental limits of resolving two distant stars, originally working
Speaker 3: within the context of radio astronomy.
Speaker 2: So you can see the clear progression here. The scientific
Speaker 2: community moved from establishing the theoretical possibility with Gotzman, to
Speaker 2: proving the hardware worked in a lab with the Harvard group,
Speaker 2: to Sajod quantifying the mathematical limits.
Speaker 3: And this current paper represents the final leap. The progression
Speaker 3: from theoretical possibility directly to a com crete receiver design.
Speaker 3: The team design the spady D multiplex are paired with
Speaker 3: the memory array and successfully replace the physical beam splitter
Speaker 3: with a functional entanglement based protocol.
Speaker 2: So once we actually build this continent size quantumie, what
Speaker 2: are we going to point it at? The scientific implications
Speaker 2: are staggering, and the authors outline some very specific astrophysical
Speaker 2: use cases.
Speaker 3: One of the primary applications is the detailed observation of star.
Speaker 2: Clusters, localizing clusters of stars right.
Speaker 3: Very often in astronomy, what appears to be a single
Speaker 3: bright point source through our current telescopes is actually a
Speaker 3: tight knot of two, three, or four separate stars orbiting
Speaker 3: each other.
Speaker 2: And distinguishing those individual stars is crucial for understanding stellar
Speaker 2: evolution and mass distribution.
Speaker 3: This quantum technology could easily unpick those type knots. But
Speaker 3: the application that truly drives the excitement in the community
Speaker 3: is exoplanet detection.
Speaker 2: The hunt for another Earth. The fundamental problem with finding
Speaker 2: exoplanets is that stars are incredibly bright and planets are
Speaker 2: incredibly dim.
Speaker 3: It is often compared to trying to spot a firefly
Speaker 3: buzzing around a massive search light from miles away. The
Speaker 3: stars glare completely washes at the planet.
Speaker 2: But the outline mentions that this quantum array has massive
Speaker 2: implications for something called nulling interferometry.
Speaker 3: Nulling interferometry is where the arbitrary measurement basis really shines.
Speaker 3: Because you control the phase measurement via quantum software, you
Speaker 3: can effectively program the virtual telescope to perfectly cancel out
Speaker 3: the specific wavefront coming from the host star.
Speaker 2: You can just turn down the starlight.
Speaker 3: You digitally cancel the spotlight, which leads only the faint
Speaker 3: offset signal of the firefly the exoplanet. And because of
Speaker 3: the unprecedented resolution of a thousand kilometer baseline, you could
Speaker 3: potentially resolve actual atmospheric features on a planet at distances
Speaker 3: we currently can't even dream of touching.
Speaker 2: That alone justifies the research, but the implications aren't just
Speaker 2: for deep space. The source material also highlights applications closer
Speaker 2: to home, specifically space domain awareness.
Speaker 3: Space domain awareness is essentially the monitoring of satellites, orbital infrastructure,
Speaker 3: and space debris.
Speaker 2: Why is this such a challenge right now? We have
Speaker 2: advanced radar systems, don't we.
Speaker 3: Radar is excellent for determining the location and trajectory of
Speaker 3: an object. But it is terrible for resolving fine visual
Speaker 3: details at orbital distances, and optical telescopes on the ground
Speaker 3: have to constantly battle the Earth's atmosphere.
Speaker 2: The atmosphere acts like a boiling soup, blurring the image.
Speaker 3: Exactly If you want to see a tool bag that
Speaker 3: drifted away from a satellite in geostationary orbit, which is
Speaker 3: thirty six thousand kilometers straight up, you need a resolving
Speaker 3: power that completely defies standard atmospheric bloring.
Speaker 2: And the quantum array solves this.
Speaker 3: It does in two ways. First, the spatial mode sorting
Speaker 3: allows you to filter out atmospheric phase noise much more
Speaker 3: effectively than a standard camera. Second, the massive state sized
Speaker 3: baseline gives you the raw resolving power to turn a
Speaker 3: single blurdy pixel into a highly detailed.
Speaker 2: Grid, soe or commercial operators could actually distinguish if a
Speaker 2: satellite has a deployed solar panel or if it has
Speaker 2: been damaged by microdebris.
Speaker 3: Or identify the specific make and model of an unknown object.
Speaker 3: The technology allows for the precise classification of objects from
Speaker 3: a known library based on high resolution geometric features. It
Speaker 3: would bring total transparency to the space domain, but.
Speaker 2: The broader impact of this technology goes far beyond just
Speaker 2: building better scientific instruments. This research feels intrinsically linked to
Speaker 2: the future of global communications. The outline points toward the
Speaker 2: quantum Internet.
Speaker 3: The connection there is fundamental think about the infrastructure required
Speaker 3: to actually build this entanglement enhanced telescope array. You need
Speaker 3: to distribute stable, entangled pairs across hundreds of thousands of kilometers.
Speaker 2: Which requires building a robust network of quantum repeaters and
Speaker 2: entanglement swapping nodes across the country.
Speaker 3: Exactly right now, conventional observatories communicate via standard fiber optic cables,
Speaker 3: sending classical digital bits. The transition proposed here requires deploying
Speaker 3: dedicated quantum communication links between these distant observatories.
Speaker 2: And once you build a network capable of reliably transmitting
Speaker 2: quibits and distributing entanglement for astronomy.
Speaker 3: You've essentially built the physical backbone of the quantum Internet.
Speaker 3: The exact same infrastructure used to perfectly syncredize telescopes can
Speaker 3: be used to transmit unhackable quantum encrypted data, or to
Speaker 3: link remote quantum computers into a single distributed mainframe.
Speaker 2: So astronomy could act as the primary driver. The initial
Speaker 2: anchor tenant that necessitates and funds the early quantum Internet infrastructure.
Speaker 3: It is a perfect synergy. It aligns entirely with the
Speaker 3: broader goals of institutions like the Center for Quantum Networks.
Speaker 3: The synthesis of these historically distinct fields quantum optics, quantum
Speaker 3: information theory, and classical observational astronomy represents a truly comprehensive
Speaker 3: solution to our most fundamental imaging limitations.
Speaker 2: To summarize the massive paradigm shift we've discussed today, the
Speaker 2: field of a astronomy is fundamentally moving from a classical
Speaker 2: model of simply gathering light to a computational model of
Speaker 2: processing quantum information.
Speaker 3: That is the core takeaway The foundational achievement of the Padilla,
Speaker 3: Guha and Sajad paper is theoretically enabling optical telescopes to
Speaker 3: finally reach the ultimate resolution allowed by the laws of
Speaker 3: quantum physics, entirely unconstrained by the physical size of the mirror.
Speaker 2: Though, as the final technical outlook makes clear, the actual
Speaker 2: realization of this theoretical model relies very heavily on the
Speaker 2: continued rapid maturation of atomic quantum memory and quantum repeater technologies.
Speaker 2: We still have to build the physical network.
Speaker 3: It is a proposal that sits right on the bleeding
Speaker 3: edge of what is experimentally possible today. But the successful
Speaker 3: merger of these sciences offers a clear pathway to observing
Speaker 3: the universe with a level of clarity that just a
Speaker 3: decade ago was thought to be strictly forbidden by physics.
Speaker 2: So here is the final provocative thought I want to
Speaker 2: leave you with as we wrap up this deep dive.
Speaker 2: We se spent four hundred years ever since Galileo, doing
Speaker 2: the exact same thing, polishing glass, trying to make the
Speaker 2: surface smoother, the parabolic curve more perfect. We eventually reached
Speaker 2: a point where we were polishing space telescope mirrors so
Speaker 2: perfectly that if you expanded them to the size of
Speaker 2: the Atlantic Ocean, the biggest bump would be smaller than
Speaker 2: a wave.
Speaker 3: And despite all that engineering perfection, we were still hitting
Speaker 3: a physical wall.
Speaker 2: Right And now we're finally realizing that the glass itself
Speaker 2: doesn't actually matter as much as the information hiding inside
Speaker 2: the light. We are realizing that the universe has been
Speaker 2: broadcasting its secrets in ultra high definition this entire time,
Speaker 2: but we've been trying to watch it on a blurry,
Speaker 2: black and white television set. Now, thanks to quantum information theory,
Speaker 2: we are finally learning how to build the four K receiver.
Speaker 2: Imagine what other signals we might find when we finally
Speaker 2: turn it on.
Speaker 3: We truly have no idea what we're going to see,
Speaker 3: and that is exactly why we built them.
Speaker 2: Thanks for joining us on this deep dive.