Operation of an atomtronic battery is demonstrated where a finite-temperature Bose–Einstein condensate stored in one half of a double-well potential is coupled to an initially empty load well that is impedance matched by a resonant terminator beam. The atom number and temperature of the condensate are monitored during the discharge cycle, and are used to calculate fundamental properties of the battery. The discharge behavior is analyzed according to a Thévenin equivalent circuit that contains a finite internal resistance to account for dissipation in the battery. Battery performance at multiple discharge rates is characterized by the peak power output, and the current and energy capacities of the system.Operation of an atomtronic battery is demonstrated where a finite-temperature Bose–Einstein condensate stored in one half of a double-well potential is coupled to an initially empty load well that is impedance matched by a resonant terminator beam. The atom number and temperature of the condensate are monitored during the discharge cycle, and are used to calculate fundamental properties of the battery. The discharge behavior is analyzed according to a Thévenin equivalent circuit that contains a finite internal resistance to account for dissipation in the battery. Battery performance at multiple discharge rates is characterized by the peak power output, and the current and energy capacities of the system.

Jan 1, 20179 citations

Principles of an atomtronic battery

Alex A. Zozulya, Dana Z. Anderson

An asymmetric atom trap is investigated as a means to implement a ``battery'' that supplies ultracold atoms to an atomtronic circuit. The battery model is derived from a scheme for continuous loading of a nondissipative atom trap proposed by Roos et al. [C. F. Roos, P. Cren, D. Guery-Odelin, and J. Dalibard, Europhys. Lett. 61, 187 (2003)]. The trap is defined by longitudinal and transverse trap frequencies ${f}_{z}$ and ${f}_{\ensuremath{\perp}}$ and corresponding trap energy heights ${U}_{z}$ and ${U}_{\ensuremath{\perp}}$. The battery's ability to supply power to a load is evaluated as a function of an input atom flux and power, ${I}_{\mathrm{in}}$ and ${P}_{\mathrm{in}}={I}_{\mathrm{in}}(1+\ensuremath{\epsilon}){U}_{z}$, respectively, where $\ensuremath{\epsilon}$ is an excess fractional energy. For given trap parameters, the battery is shown to have a resonantly optimum value of $\ensuremath{\epsilon}$. The battery behavior can be cast in terms of an equivalent circuit model; specifically, for fixed input flux and power the battery is modeled in terms of a Th\'evenin equivalent chemical potential and internal resistance. The internal resistance establishes the maximum power that can be supplied to a circuit, the heat that will be generated by the battery, and the noise that will be imposed on the circuit. We argue that any means of implementing a battery for atomtronics can be represented by a Th\'evenin equivalent and that its performance will likewise be determined by an internal resistance.An asymmetric atom trap is investigated as a means to implement a ``battery'' that supplies ultracold atoms to an atomtronic circuit. The battery model is derived from a scheme for continuous loading of a nondissipative atom trap proposed by Roos et al. [C. F. Roos, P. Cren, D. Guery-Odelin, and J. Dalibard, Europhys. Lett. 61, 187 (2003)]. The trap is defined by longitudinal and transverse trap frequencies ${f}_{z}$ and ${f}_{\ensuremath{\perp}}$ and corresponding trap energy heights ${U}_{z}$ and ${U}_{\ensuremath{\perp}}$. The battery's ability to supply power to a load is evaluated as a function of an input atom flux and power, ${I}_{\mathrm{in}}$ and ${P}_{\mathrm{in}}={I}_{\mathrm{in}}(1+\ensuremath{\epsilon}){U}_{z}$, respectively, where $\ensuremath{\epsilon}$ is an excess fractional energy. For given trap parameters, the battery is shown to have a resonantly optimum value of $\ensuremath{\epsilon}$. The battery behavior can be cast in terms of an equivalent circuit model; specifically, for fixed input flux and power the battery is modeled in terms of a Th\'evenin equivalent chemical potential and internal resistance. The internal resistance establishes the maximum power that can be supplied to a circuit, the heat that will be generated by the battery, and the noise that will be imposed on the circuit. We argue that any means of implementing a battery for atomtronics can be represented by a Th\'evenin equivalent and that its performance will likewise be determined by an internal resistance.

arXiv:1308.1331Physical Review AOct 29, 201332 citations

Experimental Realization of Atomtronic Circuit Elements in Non-Equilibrium Ultracold Atomic Systems

Seth C. Caliga

Research in the field of atomtronics aims to develop a new paradigm for the use of ultracold atomic systems in a manner that mimics the functionality of electronic circuits and devices. Given the ubiquity of the electronic transistor and its application to a vast array of signal processing tasks, the development of its atomtronic counterpart is of significant interest. This dissertation presents the experimental studies of two atomtronic circuit elements: a battery and transistor. Experiments are conducted in an atom-chip-based apparatus utilizing hybrid magnetic and optical trapping techniques that enable one to "pattern" atomtronic circuit elements. An atomtronic battery is realized in a double-well trapping potential in which a finite-temperature Bose-Einstein condensate is prepared in a non-equilibrium state to generate thermodynamic gradients that drive atom current flow. Powered by the atomtronic battery, a triple-well atomtronic transistor is demonstrated, and quasi-steady-state behavior of the device is characterized. Results are found to be in agreement with a semiclassical model of the transistor that is also used to study the active properties of the device, including current gain. Based on these results, future directions regarding signal processing operations are proposed.Research in the field of atomtronics aims to develop a new paradigm for the use of ultracold atomic systems in a manner that mimics the functionality of electronic circuits and devices. Given the ubiquity of the electronic transistor and its application to a vast array of signal processing tasks, the development of its atomtronic counterpart is of significant interest. This dissertation presents the experimental studies of two atomtronic circuit elements: a battery and transistor. Experiments are conducted in an atom-chip-based apparatus utilizing hybrid magnetic and optical trapping techniques that enable one to "pattern" atomtronic circuit elements. An atomtronic battery is realized in a double-well trapping potential in which a finite-temperature Bose-Einstein condensate is prepared in a non-equilibrium state to generate thermodynamic gradients that drive atom current flow. Powered by the atomtronic battery, a triple-well atomtronic transistor is demonstrated, and quasi-steady-state behavior of the device is characterized. Results are found to be in agreement with a semiclassical model of the transistor that is also used to study the active properties of the device, including current gain. Based on these results, future directions regarding signal processing operations are proposed.

Jan 1, 20160 citations

Dynamics of Atomtronic Battery

Hongji Yu

Atomtronics studies cold atom analogs of electric circuits. An ultra-cold Bose gas cloud trapped in a specially shaped trap can serve as a “battery” for such a circuit. We investigate the behavior of this system at different loads. We first perform a bifurcation analysis with respect to the adjustable out-coupling parameter, finding a domain where stable solutions exist and a range of initial conditions that converge to stable equilibria. We also look at the relation between the load current and chemical potential, which gives the I-V relation of the battery,and find that the model resembles an electronic battery well at low loads, but shows negative resistance at high loads. Finally we look at a few typical dynamic simulations of the system when the out-coupling strength varies in time.Atomtronics studies cold atom analogs of electric circuits. An ultra-cold Bose gas cloud trapped in a specially shaped trap can serve as a “battery” for such a circuit. We investigate the behavior of this system at different loads. We first perform a bifurcation analysis with respect to the adjustable out-coupling parameter, finding a domain where stable solutions exist and a range of initial conditions that converge to stable equilibria. We also look at the relation between the load current and chemical potential, which gives the I-V relation of the battery,and find that the model resembles an electronic battery well at low loads, but shows negative resistance at high loads. Finally we look at a few typical dynamic simulations of the system when the out-coupling strength varies in time.

Jan 1, 20160 citations

The Study of Modeled Atomtronic Barrier Potentials Through the Impedance Method

Ava Ashby

The general impedance method developed by Khondker et.al [1] is applied to multiple barrier potentials to study the transmission behaviors of a single Gaussian barrier potential, double rectangular barrier potential, and a double Gaussian barrier potential. Using the impedance method we will find quantum mechanical transmission behaviors like resonant tunneling for the quasi bound-states of the double barrier potentials. The single Gaussian barrier potential is an approximation for the atomtronic battery and the double Gaussian barrier potential is an approximation for the atomtronic transistor. Thus far, the atomtronic work presented in reference [2] was done in the classical regime where thermal currents dominate. The work presented in this thesis analyzes the quantum mechanical characteristics, such as tunneling, to be incorporated and perhaps used to explore coherent transistor action.The general impedance method developed by Khondker et.al [1] is applied to multiple barrier potentials to study the transmission behaviors of a single Gaussian barrier potential, double rectangular barrier potential, and a double Gaussian barrier potential. Using the impedance method we will find quantum mechanical transmission behaviors like resonant tunneling for the quasi bound-states of the double barrier potentials. The single Gaussian barrier potential is an approximation for the atomtronic battery and the double Gaussian barrier potential is an approximation for the atomtronic transistor. Thus far, the atomtronic work presented in reference [2] was done in the classical regime where thermal currents dominate. The work presented in this thesis analyzes the quantum mechanical characteristics, such as tunneling, to be incorporated and perhaps used to explore coherent transistor action.

Theory of Computing SystemsJan 1, 20160 citations

Principles of an atomtronic transistor

Seth C Caliga, Cameron J E Straatsma, Alex A Zozulya +1 more

A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source–gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source–gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.

arXiv:1512.04422New Journal of PhysicsJan 18, 201627 citations

{f}_{z}

and ${f}_{\ensuremath{\perp}}$ and corresponding trap energy heights

{U}_{z}

and ${U}_{\ensuremath{\perp}}$. The battery's ability to supply power to a load is evaluated as a function of an input atom flux and power,

{I}_{\mathrm{in}}

and ${P}_{\mathrm{in}}={I}_{\mathrm{in}}(1+\ensuremath{\epsilon}){U}_{z}$, respectively, where $\ensuremath{\epsilon}$ is an excess fractional energy. For given trap parameters, the battery is shown to have a resonantly optimum value of $\ensuremath{\epsilon}$. The battery behavior can be cast in terms of an equivalent circuit model; specifically, for fixed input flux and power the battery is modeled in terms of a Th\'evenin equivalent chemical potential and internal resistance. The internal resistance establishes the maximum power that can be supplied to a circuit, the heat that will be generated by the battery, and the noise that will be imposed on the circuit. We argue that any means of implementing a battery for atomtronics can be represented by a Th\'evenin equivalent and that its performance will likewise be determined by an internal resistance.