Quantum Vacuum Heterostructure Explorer

Bridging Condensed Matter and Quantum Field Theory

This simulation models a Van der Waals heterostructure bilayer hosting an excitonic-polaronic BEC superfluid, treated as an analog quantum vacuum where condensed matter phenomena map directly onto QFT/QED effects. The excitation spectrum of the condensate plays the role of the quantum field, the ordered superfluid state is the vacuum, and topological defects (vortices) serve as analogs of fundamental particles.

Unified Physics Framework

The simulation bridges the following phenomena through a single coherent physical system:

| Concept | Condensed Matter Analog | QFT/QED Counterpart | |---------|------------------------|---------------------| | Excitonic BEC | Superfluid order parameter | Vacuum state / ordered vacuum | | BKT Transition | Vortex-antivortex unbinding | Deconfinement transition | | Abrikosov Lattice | Flux quantization in B-field | Magnetic monopole lattice | | Chirality | Valley K/K' winding | Axial anomaly / handedness | | Synchrotron Radiation | Cyclotron emission from quasiparticles | Magnetobremsstrahlung | | Cherenkov Radiation | Superluminal phonon emission | Vacuum Cherenkov effect | | Phase-Locking | Goldstone/Higgs mode synchronization | Resonant cavity QED | | Schwinger Tunneling | Interlayer exciton creation | Schwinger pair production | | Unruh-DeWitt Detector | Accelerating probe in condensate | Unruh effect | | Dirac Sea / ZPF | Filled valence band + quantum depletion | Negative energy sea + vacuum fluctuations |

Quantum Heterostructure Vacuum Explorer

Material Physics

BKT transition at T/T_BKT = 1.0 — vortex unbinding
Pseudomagnetic / strain field → Abrikosov lattice density
Cherenkov threshold at v/c_s > 1.0 (Landau critical velocity)

Quantum Vacuum

Schwinger tunneling rate / exciton binding / Dirac sea visibility
Phase-locks at golden-ratio harmonics: 1.0, 1.618, 2.0, 2.618, 3.236
Unruh-DeWitt detector — thermal glow T_U = ℏa/(2πck_B)

Visualization Layers

Physics Status:
Phase-locked! Mode #2 (f=1.618) synchronized with driving frequency.
Suggested Parameter Sets:
  • Ordered Superfluid: T=0.1, B=4.0, v=0.3, Coupling=1.5, Drive=1.618 (golden ratio lock)
  • BKT Transition: Sweep T from 0.2 → 1.5 at B=3.0 — watch lattice dissolve
  • Cherenkov Onset: T=0.3, B=2.0, sweep v from 0.5 → 2.5 — Mach cone appears at v=1.0
  • Schwinger Cascade: T=0.2, Coupling=2.8 — intense interlayer tunneling events
  • Full QVC Regime: T=0.15, B=6.0, v=2.0, Coupling=2.5, Drive=2.618, Accel=4.0
Vortex Count
7
Unruh Temperature
6.10e-8 K
Cherenkov Angle
Sub-luminal

Physics of Each Layer

1. The Heterostructure Bilayer

The physical setting is a twisted Van der Waals bilayer (e.g., twisted bilayer graphene, TMD heterostructure). Two 2D crystalline layers are stacked with a small twist angle, creating a moire superlattice:

V_moire(r) = 2w cos(G_1 . r) + 2w cos(G_2 . r) + 2w cos(G_3 . r)

Where G_i are moire reciprocal lattice vectors and w is the interlayer coupling. At the "magic angle" (~1.1 degrees for graphene), flat bands emerge with:

The hexagonal grid visualization shows the two lattice orientations with their slight twist.

2. Excitonic-Polaronic BEC

In the flat bands, excitons (electron-hole bound pairs) or polarons (electrons dressed by phonon clouds) can condense into a Bose-Einstein Condensate:

Order Parameter (Gross-Pitaevskii):

ihbar d_psi/dt = [-hbar^2 nabla^2 / (2m*) + V_ext + g|psi|^2 + V_dd] psi

Where:

The condensate exhibits:

In the simulation, 5000 green-cyan particles represent the condensate density between the bilayer planes.

3. BKT Vortex Proliferation

In 2D systems, the superfluid transition follows the Berezinskii-Kosterlitz-Thouless mechanism rather than conventional Landau theory:

Below T_BKT:

At T_BKT:

k_B T_BKT = (pi/2) rho_s hbar^2 / m*

Pairs unbind. The superfluid stiffness rho_s drops discontinuously to zero.

Above T_BKT:

In the simulation: The Temperature slider drives this transition. Watch the ordered Abrikosov lattice dissolve as T crosses T_BKT = 1.0, with free vortices appearing randomly.

4. Abrikosov Vortex Lattice

When an effective magnetic field penetrates the superfluid (from Berry curvature, strain-induced pseudomagnetic field, or external field), quantized vortices nucleate and self-organize:

Flux quantization:

Phi_0 = h / (2e*) = pi hbar / e*

Vortex density:

n_v = B / Phi_0

The vortices minimize their mutual repulsion by forming a triangular (Abrikosov) lattice. This is the same physics as Type-II superconductors in the mixed state.

In the simulation: Red cores (CW chirality) and blue cores (CCW chirality) form the lattice. Increase B-field to see more vortices pack into the disc.

5. Chirality

The valley degree of freedom (K vs K' in the Brillouin zone) provides intrinsic chirality:

In the simulation: Red/blue vortex cores indicate CW/CCW winding. Edge current particles flow in opposite directions on top/bottom layers. Near CW vortices, condensate shifts warm (red); near CCW, shifts cool (blue).

6. Synchrotron Radiation (Magnetobremsstrahlung)

Charged quasiparticles (excitons have dipole moments, polarons carry charge) spiraling in the effective B-field emit cyclotron/synchrotron radiation:

Cyclotron frequency:

omega_c = e*B / m*

Radiated power (Larmor):

P = e*^2 a^2 / (6 pi epsilon_0 c^3)

For relativistic particles, radiation is confined to a narrow forward cone of half-angle ~1/gamma. In the condensed matter context, this manifests as emission at cyclotron harmonics.

In the simulation: 6 bright particles spiral above the bilayer with glowing trails. Higher B-field = tighter orbits, faster cycling, more radiation.

7. Cherenkov Radiation

When a vortex moves faster than the Landau critical velocity (the superfluid speed of sound), it emits a Mach cone of phonon radiation:

Landau critical velocity:

v_L = min(epsilon(p) / p)

For a weakly interacting BEC: v_L = c_s = sqrt(gn/m*) (Bogoliubov sound speed).

Mach cone half-angle:

sin(theta) = c_s / v = 1 / M

Where M = v/c_s is the Mach number. This is the direct superfluid analog of optical Cherenkov radiation, confirmed experimentally in superfluid helium and atomic BECs.

In the simulation: When Vortex Velocity exceeds 1.0 (the Landau critical velocity), a blue Mach cone appears trailing the fast-moving vortex. The cone narrows at higher speeds.

8. Resonant/Harmonic Phase-Locking

The condensate supports collective modes that can synchronize with external driving:

Phase-locking occurs when the driving frequency matches a natural mode:

|omega_drive - omega_n| < Delta omega_lock

The locking bandwidth Delta omega_lock depends on coupling strength. The simulation uses golden-ratio harmonics (1.0, 1.618, 2.0, 2.618, 3.236) as natural frequencies, reflecting the self-similar structure of moire superlattices.

In the simulation: Torus rings represent collective modes. When Driving Frequency matches a harmonic, the ring turns gold and stabilizes (phase-locks). Try sweeping the frequency to find each resonance.

9. Coulomb/Schwinger Barrier Tunneling

Interlayer exciton creation is a tunneling process through the Coulomb barrier separating the layers. At high interlayer coupling, this becomes analogous to Schwinger pair production:

Schwinger pair production rate:

Gamma ~ (alpha E^2 / pi) exp(-pi E_c / E)

Condensed matter analog: Virtual excitons tunnel through the interlayer barrier. At high coupling (strong effective field), the barrier becomes thin enough for spontaneous pair creation:

Gamma_tunnel ~ omega_0 exp(-2 integral sqrt(2m*(V(x) - E)) / hbar dx)

QVC connection: This is the mechanism by which vacuum energy manifests as real excitations. The stronger the interlayer coupling, the more the vacuum "leaks" through the barrier.

In the simulation: Green flashes between the layers represent tunneling events. Rate increases exponentially with Interlayer Coupling. Each event shows an exciton traversing from bottom to top layer.

10. Unruh-DeWitt Detector and Vacuum Polarization

An Unruh-DeWitt detector is a two-level system (quantum dot, impurity) coupled to the field:

Unruh temperature:

T_U = hbar a / (2 pi c k_B)

A detector with proper acceleration a through the condensate vacuum perceives thermal radiation at temperature T_U. This is the condensed matter analog of the Unruh effect: the excitation spectrum of the condensate appears thermal to an accelerating observer.

Vacuum polarization manifests as screening: the condensate's virtual excitations dress the bare Coulomb interaction, modifying it from 1/r to a Yukawa-like screened potential.

In the simulation: The golden diamond probe orbits above the bilayer. Higher Probe Acceleration = brighter thermal glow (Unruh radiation) and stronger vacuum excitation.

11. Dirac Sea and Zero-Point Field

The filled valence band of the heterostructure IS the Dirac sea (literally, in graphene with its Dirac cone dispersion):

Zero-point energy:

E_ZPF = sum_k (1/2) hbar omega_k

Quantum depletion of the condensate represents zero-point fluctuations:

n_depleted / n_total ~ (na_s^3)^(1/2) / (3 pi^2)

Virtual pair bubbles in the Dirac sea represent vacuum fluctuation events. These become more frequent (more visible) as interlayer coupling increases, reflecting enhanced vacuum polarization.

In the simulation: Deep purple particles below the bilayer form the Dirac sea. Cyan-magenta pair bubbles appear and annihilate. Opacity scales with interlayer coupling (vacuum activity).

Mathematical Unification

The Central Equation

All phenomena connect through the effective action of the condensate coupled to the vacuum:

S_eff = integral d^3x dt [
  ihbar psi* d_t psi                           (condensate dynamics)
  - hbar^2/(2m*) |nabla psi|^2                 (kinetic energy)
  - V_ext |psi|^2                               (trapping potential)
  - (g/2)|psi|^4                                (contact interaction)
  - psi* V_dd * psi                             (dipolar interaction)
  + sum_k hbar omega_k (a_k^dag a_k + 1/2)     (vacuum modes / ZPF)
  + lambda psi* psi sum_k (a_k + a_k^dag)      (condensate-vacuum coupling)
  + e* A_mu j^mu                                (gauge coupling / B-field)
]

The lambda coupling term is the QVC mechanism: it connects the condensate order parameter to vacuum mode creation/annihilation operators. When driven resonantly, this coupling enables energy transfer between the vacuum and the condensate.

Topological Invariants

The system carries topological charges:

Vortex winding number:

n_w = (1/2pi) oint nabla theta . dl = +/- 1, +/- 2, ...

Berry phase (Chern number):

C = (1/2pi) integral_BZ Omega(k) d^2k

BKT renormalization group flow:

dK/dl = -4 pi^3 y^2
dy/dl = (2 - pi K) y

Where K = rho_s/(k_B T) is the stiffness and y = exp(-E_core/k_B T) is the vortex fugacity.

Experimental Relevance

Platforms Where This Physics Occurs

  1. Twisted Bilayer Graphene (TBG): Magic-angle superconductivity, correlated insulators, excitonic phases
  2. TMD Heterostructures (MoSe2/WSe2): Interlayer excitons with ~100 meV binding energy, moire potential
  3. Exciton-Polariton Condensates: Microcavity photon + exciton quasiparticles, BKT transition observed
  4. Superfluid Helium Films: 2D BKT physics, quantized vortices, third sound
  5. Cold Atom Bilayers: Optical lattice + synthetic gauge fields, tunable interactions

What Has Been Observed

Open Questions for QVC Theory

Simulation Details

This real-time 3D visualization renders:

Total: ~7,400+ particles + dynamic geometry at 60 FPS via WebGL.

Controls Reference

| Control | Range | Physics | |---------|-------|---------| | Temperature | 0 - 2.0 T/T_BKT | BKT transition, thermal noise, coherence | | B-Field | 0 - 8.0 | Abrikosov lattice density, cyclotron frequency | | Vortex Velocity | 0 - 3.0 v/c_s | Cherenkov threshold at 1.0 | | Interlayer Coupling | 0 - 3.0 | Schwinger tunneling, Dirac sea visibility | | Driving Frequency | 0.1 - 5.0 | Phase-locking at golden-ratio harmonics | | Probe Acceleration | 0 - 5.0 | Unruh-DeWitt thermal response |