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A Physicist’s Perspective on Electronics

A Physicist’s Perspective on Electronics. Development History Mechanics -- Electronics Materials Faster and Smaller Example 1: Cold, Small, and Delicate Example 2: Simple, but Novel. Mechanics. Give me a place to stand and I will move the Earth. Energy Transfer is Useful!.

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A Physicist’s Perspective on Electronics

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  1. A Physicist’s Perspective on Electronics Development History Mechanics -- Electronics Materials Faster and Smaller Example 1: Cold, Small, and Delicate Example 2: Simple, but Novel

  2. Mechanics Give me a place to stand and I will move the Earth.

  3. Energy Transfer is Useful! Overcome friction to implement nearly ideal behavior… …or maintain the integrity of a signal…

  4. …or manipulate information through the storage and combination of logical symbols…

  5. …or allow low power “signals” to control high power events.

  6. Electricity and Magnetism New forces couple to mechanics -- motors and generators Electrical energy is very portable – wires, waveguides ,and waves Conversion to other forms is easy – transducers  Perfect for manipulation of information!

  7. Electrical Switching and Amplifying What’s the equivalent of the capstan for electricity? small influence  large influence  Amplifying Relay Vacuum Tube Transistor

  8. Electrical Switching and Amplifying Analog operations…. Logic operations….

  9. Electronics Mechanics Force Motion Rope or Shaft Friction Elastic Stress Inertia Voltage Current Wire Resistor Capacitor Inductor

  10. Sea of free electrons in a lattice of immobile ions • Bulk charge is neutral • Electrons act like an incompressible liquid confined to the metal Wire: Materials – Metal Long wires can apply forces (voltage) over long distances. 1000 electrons in Inside: 1019/cm3 1000 electrons out 1 A through , 1 mm dia. ~ 1 m/s Influence at light speed! Relay switches by physical contact.

  11. Empty space – ballistic motion, with space charge • Electrons and beams of manipulated by fields Materials – Vacuum Grid -1 V Plate +1000 V Large e- Current Heater 0 V

  12. Pure crystalline semiconductor (Si) is insulating at low temperature • Carrier concentration is tuned by Si substitution (doping) density • Carrier sign either positive (Al) or negative (P) • Ballistic (Vacuum)  Doping Level  Hydrodynamic (Metal) Materials – Semiconductor Silicon PN Junction Diode Depletion Region Current – Voltage Relation V V=0 Holes (+) Electrons (-) A Cathode Anode

  13. Gate Field Effect Transistor N Channel Si Substrate Gate N Channel FET • Depletion region controlled by gate voltage • Physical channel width changes with depletion • Gate voltage controls channel current • Gate is reverse biased with respect to channel so very little current flows • Constructed by deposition, diffusion, and etching

  14. Product of natural evolution! • Signals are action potential (voltage) pulses • Propagation and amplification are integrated in axons • Neurons act like logic gates Materials – Axons and Neurons …an amazing combination of analog and digital processing.

  15. Relay, Vacuum Tube; Transistor; Quantum Dot; Single Atom Faster and Smaller Through History We are here: E.Scheer, Nature Nanotechnology 8, 645 (2013) Why small? • Faster with less charging • Less power

  16. Relay Circuits Frankfurt Central Station (Arne Hückelheim)

  17. Tube Circuits -- EDSAC

  18. Transistor Circuits -- UNIVAC Dual NOR gate module Development of the printed circuit

  19. Integrated Circuit Printed circuit on silicon -- Fairchild (1963) mA741 (1968, above)

  20. Cell Phone Innards Current Commercial Technology Resistors, capacitors, inductors, diodes, transistors, integrated circuits (No tubes or relays)

  21. Integrated Circuit

  22. Are we near the end?

  23. 1 cm3 Not even close! 1 cm2  Typical Neural Density, cm-3 | 1 nm | (E. Scheer, et. al.)

  24. Instrumentation – Low power thickness transducer allows for non-intrusive detection of superfluid film oscillations near absolute zero. Fundamental Concepts – Simple (and first) experimental demonstration of PT symmetric temporal dynamics. Two Examples…

  25. Oscillations of a Superfluid Film • T ~ 0.1 K • Film ~ 8 helium atoms thick in Bose condensed quantum state • Lateral sloshing produces small thickness changes • Film flow is produced and observed by the sloshing • Exotic flow phenomena probe many body quantum mechanics

  26. Tunnel diode drives the oscillator Signal returnsencoded as a modulated 100 MHz voltage Thickness Detection Supply DC power from room temperature Film thickness modulates a 10 pF capacitance Capacitance is incorporated into a 100 MHz oscillator • Tunnel diode provides negative resistance gain • Quantum tunneling works better at lower temperatures • Power less than 300 nW • Very stable oscillator – noise level ~ 200 fm in a 1 Hz bandwidth • One coaxial connection supplies power and returns the signal

  27. Ideas originated in a quantum mechanical context • Adopted by the optics community promising exotic behavior Dynamical Systems with PT Symmetry(With T. Kottos) • Novel interference effects • Non-reciprocal transmission • Required conditions difficult to achieve with optics • Principles and new directions demonstrated with electronic equivalents

  28. The PT dimer… Parity and Time Reversal Symmetry Gain Side Loss Side Not parity symmetric – switching left and right is different Not time symmetric – switching forward and backward is different PT symmetric – switching both left and right AND forward and backward IS the same Purposely increasing loss (along with gain) is not intuitively advantageous!

  29. Nonreciprocal Transmission N. Bender, et al., Phys. Rev. Lett., 110, 234101 (2013) Adding transmission lines and a nonlinearity to the gain/loss elements results in greatly enhanced isolation. We demonstrated the principle, others followed with an optical version. B. Peng, et al., Nature Physics, 10, 394 (2014)

  30. Other promising directions... Higher frequencies will allow us to expand beyond a “proof of principle” role into practical engineered devices. Dynamic matching of antenna impedance for wireless or radar applications. Time modulated inter-oscillator coupling shows promise for even more exotic applications.

  31. Theory (Tsampikos Kottos) • Nick Bender • Junsik Lee • Zin Lin • Hamid Ramezani • Josh Bodyfelt • Mei Zheng • Experiment (Fred Ellis) • Mahbube Chitsazi • Sam Factor • Joe Schindler • Yudhiakto Pramudya • Support • Wesleyan Project grant • Wesleyan Internship • NSF DMR

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